TEST BANK for Principles of Development 6th Edition by Lewis Wolpert, Cheryll Tickle and Alfonso Mar by StudyGuide

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 01 - Question 01 01) Which of these terms refers to the “generation of form?” a. Developmental biology Feedback: No, developmental biology is the field of biology focused on understanding how animals and plants develop. Page reference: 2 b. Embryogenesis Feedback: No, embryogenesis is the development of an embryo from a fertilized egg. Page reference: 2 *c. Morphogenesis Feedback: Yes, morphogenesis is the development of form. The meaning comes from the words “morph” (form) and “genesis” (generation of). Page reference: 2 d. Embryology Feedback: No, embryology is an outdated term to describe the study of developmental biology. Modern developmental biologists appreciate that development of an organism continues after embryogenesis. Page reference: 3 Type: multiple choice question Title: Chapter 01 - Question 02 02) Which of these is true of meiosis? *a. Germ cells are formed through this process. Feedback: Yes, this is true. Germ cells, sperm and egg, are formed when a diploid cell undergoes meiosis to give rise to four cells containing half the number of chromosomes (haploid). Page reference: 6 b. A zygote is formed through this process. Feedback: No, this is not true. A zygote is formed when fusion of a haploid egg nucleus with a haploid sperm nucleus takes place. Page reference: 5 c. This process is carried out during cleavage stage. Feedback: No, this is not true. Cleavage stage is when a single-celled zygote undergoes rapid mitotic cell divisions. Page reference: 14 d. Daughter somatic cells are formed containing the same number of chromosomes as the parental cell. Feedback: No, this is not true. Mitosis is the type of cell division somatic cells use to keep the number of chromosomes constant from parental cell to daughter cells. Page reference: 5 Type: multiple choice question Title: Chapter 01 - Question 03 03) What is the key hypothesis of a mosaic model for developmental fate regulation? a. Normal development occurs even if cells are removed. Feedback: No, if normal development proceeds even after cell removal this highlights an embryo’s ability to regulate for this cell loss. This is the opposite of mosaic development where cytoplasmic determinants are specific to a subset of embryonic cells. Page reference: 24 b. Zygotic proteins and RNAs are equally distributed to daughter cells Feedback: No, zygotic cytoplasmic determinants are expected to be unequally distributed among daughter cells during cleavage events. This is how subpopulations of embryonic cells would establish different characteristics within the context of a mosaic model. Page reference: 24

Wolpert et al, Principles of Development 6e Test bank *c. Patterns of cell division control embryonic cell fate. Feedback: Yes, cytoplasmic determinants within the zygote are distributed unequally within daughter cells during cleavage stage. Each cell’s determinants control the future fate of that cell. Page reference: 24 d. Cells within an early embryo communicate with each other. Feedback: No, cell-cell communication is a key expectation of cells within an embryo capable of regulating for cell loss. It is understood that communication is necessary for sensing cell loss. Page reference: 24 Type: multiple choice question Title: Chapter 01 - Question 04 04) The influence of one cell over another neighbouring cell’s development is called. a. Interaction Feedback: No, induction is where one cell, or tissue, directs the development of another neighbouring cell or tissue through cell-cell signalling. Page reference: 8 b. Communication Feedback: No, induction is where one cell, or tissue, directs the development of another neighbouring cell or tissue through cell-cell signalling. Page reference: 8 c. Organization Feedback: No, induction is where one cell, or tissue, directs the development of another neighbouring cell or tissue through cell-cell signalling. Page reference: 8 *d. Induction Feedback: Yes, induction is where one cell, or tissue, directs the development of another neighbouring cell or tissue through cell-cell signalling. Page reference: 8 Type: multiple choice question Title: Chapter 01 - Question 05 05) Which of the options given is not true of the Spemann-Mangold organizer experiment? a. The transplanted tissue is the dorsal lip of the blastopore. Feedback: No, this is true. The transplanted tissue is the dorsal lip of the blastopore from an unpigmented embryo. Page reference: 8 b. A secondary body axis developed, containing neural tube and somites. Feedback: No, this is true. The dorsal blastopore lip transplantation into the ventral surface of another embryo induced a secondary axis. Page reference: 8 c. The transplanted tissue resides near the region where gastrulation begins. Feedback: No, this is true. The blastopore is the site where gastrulation begins in the newt. The dorsal lip of the slit-like invagination is the organizer tissue. Page reference: 8 *d. Every induced tissue was pigmented. Feedback: No, this is not true. Tissues within the induced secondary axis contained cells of graft (unpigmented) and host (pigmented) origin. This suggests that cells within the graft tissue send inductive signals to the host tissue. Page reference: 8 Type: multiple choice question Title: Chapter 01 - Question 06 06) Which developmental process establishes a coordinate system whereby cells “know” their location within an embryo?

Wolpert et al, Principles of Development 6e Test bank a. Morphogenesis Feedback: No, morphogenesis is the generation of form through cell shape change and movements. Page reference: 16 b. Cell differentiation Feedback: No, differentiation is the process of cells becoming structurally and functionally different from each other, ending up as distinct specialized cell types. Page reference: 16 *c. Pattern formation Feedback: Yes, pattern formation involves the establishment of a body plan with defined main body axes. Cells with knowledge of their spatial position along the anterio-posterior, dorsoventral, and right-left axes can develop accordingly. Page reference: 14 d. Growth Feedback: No, growth is the increase in size. Growth can occur through increases in cell number or size. Page reference: 16 Type: multiple choice question Title: Chapter 01 - Question 07 07) Pancreatic and muscle cells are specialized to perform distinct functions but contain the exact same set of genetic instructions. Which of the options given does not represent a mechanism to accomplish this? *a. Differentiated cells lose genes that are unrelated to their function. Feedback: Yes, this is not a proper mechanism. Animal cloning experiments, such as the one performed by John Gurdon, suggest that adult differentiated cells contain the same set of genetic instructions as cells within the early embryo. Page reference: 19 b. Differentiated cells contain distinct gene-regulatory proteins Feedback: No, this is a proper mechanism. Gene regulatory proteins, in different combinations, determine the list of genes that are expressed in specific cell types within the organism. Page reference: 19 c. Differentiated cells use distinct gene control regions. Feedback: No, this is a proper mechanism. Gene regulatory proteins, in different combinations, bind to and activate or repress specific DNA control regions. This creates a bank of expressed cell-specific genes that dictates a cell’s function. Page reference: 20 d. Differentiated cells undergo specific types of post-translational protein modification. Feedback: No, this is a proper mechanism. Even if a gene is expressed and the protein produced, cells can modify the same protein differently between cell types. This can lead to differences in cellular behaviour. Page reference: 18 Type: multiple choice question Title: Chapter 01 - Question 08 08) What do we call a group of cells that differentiates according to its normal fate after it has been isolated from the embryo and cultured in a neutral environment? a. Determined Feedback: No, determination is assessed by transplanting cells from their normal embryonic region to an ectopic embryonic region and observing their fate. Page reference: 22 b. Chimeric Feedback: No, a chimera is a mosaic of cells with different genetic make-up. Page reference: 24

Wolpert et al, Principles of Development 6e Test bank *c. Specified Feedback: Yes, an isolated cell is said to be specified if its final differentiated state in isolation mimics its expected embryonic fate. Page reference: 22 d. Competent Feedback: No, competence is a term used to describe a cell’s ability to receive and respond to an inductive signal. Page reference: 25 Type: multiple choice question Title: Chapter 01 - Question 09 09) Which of the options given is not true of the French flag mechanism of pattern formation? *a. Differing concentrations of a teratogen provide positional values. Feedback: Yes, this is not true. Differing concentrations of morphogens provide positional values by diffusing away from a source. Teratogens are chemicals that cause abnormal development. Page reference: 29 b. Cells develop according to threshold concentrations of a molecule. Feedback: No, this is true. Cells that receive a morphogen above a particular concentration develop differently than nearby cells that receive a morphogen below that concentration threshold. Page reference: 29 c. Experiments using amphibian and insect limbs were among the first to lend support to this model. Feedback: No, this is true. Regenerating amphibian and insect limbs, in which they regenerated missing tissues, played a key part in the establishment of this model. It is understood that regenerating tissues must acknowledge their position in order to know what is missing and to replace it in the correct spatial position. Page reference: 29 d. The model gets its name from the three colors of the French flag (blue, white, red). Feedback: No, this is true. The three domains of color within the flag represent three regions of cells receiving differing concentration thresholds of a morphogen along a line. Cells within each domain establish distinct genetic programs that define their fate. Page reference: 27 Type: multiple choice question Title: Chapter 01 - Question 10 10) A human zygote, which has the potential to give rise to a complete new human, is often described as what type of cell? a. Unipotent Feedback: No, a unipotent cell can only give rise to one type of cell. Page reference: 31 b. Multipotent Feedback: No, a multipotent cell has the potential of differentiating into many, but not all cell types. Its fate is far more restricted than a pluripotent cell. Page reference: 31 *c. Totipotent Feedback: Yes, a human zygote is the only cell known to have the potential of giving rise to a complete new human. We refer to the zygote as totipotent. Page reference: 32 d. Pluripotent Feedback: No, pluripotent cells have the potential to give rise to all the cells in the body but haven’t been shown to be able to give rise to a complete new human on their own. Page reference: 31

Wolpert et al, Principles of Development 6e Test bank

Wolpert et al, Principles of Development 6e Test bank Type: MC question Title: Chapter 02 - Question 01 01) What is the result of the first 12 nuclear divisions of a Drosophila embryo where roughly 6,000 nuclei share a single cytoplasm? a. Micropyle @ No, a micropyle is the structure through which sperm enters the anterior end of the egg. Page reference: 38 b. Cellular blastoderm @ No, the cellular blastoderm occurs only after membranes form around peripheral nuclei. A single cytoplasm is no longer shared at this point as cellularization has taken place. Page reference: 39 *c. Syncytium @ Yes, the first twelve nuclear divisions occur without cytokinesis to give rise to a single cytoplasm containing roughly 6,000 nuclei. This single cell is referred to as a syncytium. Page reference: 38 d. Pole cell @ No, pole cells are a small population of individual cells that will become germ cells from which the gametes will be derived. Page reference: 40 Type: MC question Title: Chapter 02 - Question 02 02) Which of the options given is not true of the Drosophila mesoderm? a. It gives rise to muscle and connective tissue. @ No, this is true. Muscle and connective tissue are important mesoderm-derived tissues in vertebrate and invertebrate embryos. Page reference: 40 b. Gastrulation internalizes the mesoderm. @ No, this is true. Cellular rearrangements during gastrulation forces blastoderm cells to the interior of the embryo. Page reference: 40 c. The mesoderm is a primary germ layer. @ No, this is true. The mesoderm is a primary germ layer, along with endoderm and ectoderm. Page reference: 40 *d. The dorsal surface of the blastoderm gives rise to mesoderm. @ Yes, this is not true. Gastrulation forces ventral blastoderm cells into the interior of the embryo, thus forming the mesoderm. Page reference: 40 Type: MC question Title: Chapter 02 - Question 03 03) Which term is not associated with a Drosophila larva? a. Instar @ No, an instar is a larval stage with successive periods of growth, molting, and shedding. Page reference: 41 *b. Metamorphosis @ Yes, metamorphosis is a process within a pupa where a major transformation of the adult form takes place. The pupal stage occurs after the larval stage. Page reference: 41 c. Denticles @ No, denticles are belts of small tooth-like outgrowths from the epidermal cuticle. Page reference: 41 d. Imaginal discs

Wolpert et al, Principles of Development 6e Test bank @ No, imaginal discs are small sheets of epidermal cells from which adult tissues, like legs and wings, are derived. Imaginal discs undergo cell proliferation during larval stages. Page reference: 41 Type: MC question Title: Chapter 02 - Question 04 04) What is the maternal anterior morphogen that controls head and thorax development? *a. Bicoid @ Yes, bicoid mRNA translation at fertilization gives rise to an anterior to posterior gradient that is required for development of anterior structures. Page reference: 47 b. Nanos @ No, nanos mRNA translation at fertilization gives rise to a posterior to anterior gradient that is required for development of posterior structures. Page reference: 47 c. Caudal @ No, caudal mRNA translation at fertilization gives rise to a posterior to anterior gradient that is required for development of posterior structures. Page reference: 50 d. Torso @ No, Torso is required for development of the extreme ends (acron and telson) of the embryo. Page reference: 51 Type: MC question Title: Chapter 02 - Question 05 05) Which of the options given is not true of the Drosophila Dorsal protein? a. Control regions of target genes differ in their affinity for the Dorsal protein. @ No, this is true. Dorsal protein can bind with different affinity to control regions of its target genes. This characteristic adds to the complexity of target gene expression across the dorsoventral axis of the Drosophila embryo. Page reference: 62 b. The dorsal region of the Drosophila embryo expresses genes that are repressed by the Dorsal protein. @ No, this is true. Dorsal protein can act as repressor and activator of gene expression. Because Dorsal protein is high in the ventral region, repressed genes show expression within dorsal cells of the Drosophila embryo. Page reference: 62 c. The gradient of Dorsal protein divides the Drosophila embryo up into at least four well-defined domains. @ No, this is true. A French flag model can be invoked to describe the patterning of the dorsoventral axis within the Drosophila embryo. Page reference: 62 *d. Dorsal protein levels are higher within the dorsal region of the Drosophila embryo. @ Yes, this is not true. Dorsal protein levels are higher within the ventral region of the Drosophila embryo. Page reference: 62 Type: MC question Title: Chapter 02 - Question 06 06) What class of patterning genes are expressed within seven transverse stripes in the Drosophila embryo? *a. Pair-rule genes @ Yes, pair-rule genes are expressed in seven transverse stripes within alternating parasegments.

Wolpert et al, Principles of Development 6e Test bank Page reference: 72 b. Segmentation genes @ No, segmentation genes are expressed in 14 transverse stripes. Page reference: 76 c. Gap genes @ No, gap genes are expressed in broad regions. Page reference: 66 d. Hox genes @ No, Hox genes are expressed in broad regions along the anterio-posterior axis. Page reference: 84 Type: MC question Title: Chapter 02 - Question 07 07) What class of patterning genes encodes members of intercellular signaling pathways? a. Pair-rule genes @ No, pair-rule genes encode transcription factors that function within a syncytium prior to cellularization. Page reference: 72 *b. Segmentation genes @ Yes, segmentation genes function after the blastoderm becomes cellularized. Therefore, signaling proteins and their receptors are necessary to define parasegment boundaries. Page reference: 78 c. Gap genes @ No, gap genes encode transcription factors that function within a syncytium prior to cellularization. Page reference: 66 d. Hox genes @ No, all Hox genes encode transcription factors that define the identity of embryonic segments. Page reference: 85 Type: MC question Title: Chapter 02 - Question 08 08) Which of these segmentation genes is a transcription factor that defines parasegment boundaries? a. Frizzled @ No, Frizzled is the receptor for the Wingless signaling protein. Page reference: 78 b. Hedgehog @ No, Hedgehog is an intercellular signaling protein. Page reference: 78 c. Patched @ No, Patched is the receptor for the Hedgehog signaling protein. Page reference: 78 *d. Engrailed @ Yes, Engrailed is a transcription factor that limits the pattern of Hedgehog and Wingless signaling pathways to define parasegment boundaries. Page reference: 78 Type: MC question Title: Chapter 02 - Question 09 09) What is the term that describes the relation between the order of the Hox genes along the chromosome and the order of their expression along the antero-posterior axis? a. Homeosis @ No, homeosis is the transformation of a whole segment into another related one.

Wolpert et al, Principles of Development 6e Test bank Page reference: 85 b. Posterior dominance @ No, posterior dominance is the phenomenon in which Hox gene products normally expressed in anterior regions are suppressed by more posterior products. Page reference: 87 c. Gene cluster @ No, Hox genes are organized into two clusters of genes that make up the HOM-C complex. Page reference: 91 *d. Co-linearity @ Yes, co-linearity refers to the correspondence between the order of Hox genes along the chromosome and the order in which they are expressed along the antero-posterior axis of the embryo. Page reference: 93

Type: MC question Title: Chapter 02 - Question 10 10) What type of gene, such as a Hox gene, is sufficient to cause cells to adopt a particular fate? *a. Selector @ Yes, a selector gene’s activity is sufficient to cause cells to adopt a particular fate. Page reference: 77 b. Repressor @ No, a selector gene’s activity is sufficient to cause cells to adopt a particular fate. A repressor protein represses a gene’s expression. Page reference: 62 c. Activator @ No, a selector gene’s activity is sufficient to cause cells to adopt a particular fate. An activator protein activates a gene’s expression. Page reference: 62 *d. Recessive @ No, recessive is just a general name for any gene that only shows a normal phenotype when two copies are present in the cell. Page reference: 43

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 03 - Question 01 01) Which embryonic axis do axial structures, such as the neural tube and notochord, “run” along? a. Dorso-ventral Feedback: No, the dorso-ventral axis runs from back to belly within a vertebrate embryo. Page reference: 94 *b. Antero-posterior Feedback: Yes, the antero-posterior axis is the main axis of a vertebrate embryo with the head at the anterior end. Page reference: 94 c. Proximo-distal Feedback: No, the antero-posterior axis is the main axis of a vertebrate embryo with the head at the anterior end. Page reference: 94 d. Left-right Feedback: No, the antero-posterior axis is the main axis of a vertebrate embryo with the head at the anterior end. Page reference: 94 Type: multiple choice question Title: Chapter 03 - Question 02 02) Which of these groups consist solely of amniote embryos? a. Frog, chicken, mouse Feedback: No, amniotes form an extra-embryonic membrane called the amnion. Amphibians are not amniotes. Page reference: 97 b. Fish, frog, mouse Feedback: No, amniotes form an extra-embryonic membrane called the amnion. Fish and amphibians are not amniotes. Page reference: 97 c. Fish, human, chicken Feedback: No, amniotes form an extra-embryonic membrane called the amnion. Fish are not amniotes. Page reference: 97 *d. Human, chicken, mouse Feedback: Yes, amniotes form an extra-embryonic membrane called the amnion. Humans, chickens, and mice are all amniotes. Page reference: 97 Type: multiple choice question Title: Chapter 03 - Question 03 03) What is the name for the ball of cells created through cleavage of the frog zygote? *a. Blastula Feedback: Yes, cleavage patterns give rise to a ball of cells of different sizes and amounts of yolk. The embryo at this point is called a blastula. Page reference: 99 b. Blastopore Feedback: No, the blastopore is a small slit-like infolding that forms on the surface of a blastula and is an important site for cell involution during gastrulation. Page reference: 99 c. Blastocoel Feedback: No, the blastocoel is a fluid-filled cavity that develops within the animal region of a blastula.

Wolpert et al, Principles of Development 6e Test bank Page reference: 99 d. Blastomere Feedback: No, blastomeres are the individual cells formed within the blastula as a result of cleavage events. Because no growth occurs between each cell division, blastomeres become successively smaller as cleavage occurs. Page reference: 99 Type: multiple choice question Title: Chapter 03 - Question 04 04) What germ layer undergoes neurulation? a. Endoderm Feedback: No, neurulation is the process whereby the ectoderm folds up to form the neural tube. Page reference: 100 *b. Ectoderm Feedback: Yes, neurulation is the process whereby the ectoderm folds up to form the neural tube. Page reference: 100 c. Intermediate mesoderm Feedback: No, neurulation is the process whereby the ectoderm folds up to form the neural tube. Page reference: 100 d. Lateral plate mesoderm Feedback: No, neurulation is the process whereby the ectoderm folds up to form the neural tube. Page reference: 100 Type: multiple choice question Title: Chapter 03 - Question 05 05) What is the chick equivalent of the Spemann organizer in amphibians? a. Primitive streak Feedback: No, the primitive streak is the equivalent to the amphibian blastopore. Hensen’s node is the anterior-most region of the primitive streak and is the major organizing center for an early chick embryo. Page reference: 105 *b. Hensen’s node Feedback: Yes, Hensen’s node is the anterior-most region of the primitive streak and is the major organizing center for an early chick embryo. Page reference: 107 c. Koller’s sickle Feedback: No, Koller’s sickle is a crescent-shaped ridge of cells located at the boundary between the area opaca and area pellucida at the posterior end of the chick embryo. It defines the position in which the primitive streak will form. Hensen’s node is the anterior-most region of the primitive streak and is the major organizing center for an early chick embryo. Page reference: 106 d. Epiblast Feedback: No, the epiblast is the upper layer of the blastoderm. Cells within this layer ingress through the primitive streak and past Hensen’s node to construct the endoderm and mesoderm. Hensen’s node is the anterior-most region of the primitive streak and is the major organizing center for an early chick embryo. Page reference: 105 Type: multiple choice question Title: Chapter 03 - Question 06 06) Which animal embryo does not develop from a blastodisc? *a. Mouse Feedback: Yes, the mouse (and other rodent) embryos are peculiar in that the epiblast is cupshaped rather than flat and disc-like.

Wolpert et al, Principles of Development 6e Test bank Page reference: 112 b. Human Feedback: No, human embryos are different from mouse embryos in this respect. Human epiblasts resemble the flat blastodisc of chicken and rabbit embryos. Page reference: 113, 133 c. Chick Feedback: No, chick embryos are different from mouse embryos in this respect. Chick epiblasts resemble the flat blastodisc of human and rabbit embryos. Page reference: 120 d. Rabbit Feedback: No, rabbit embryos are different from mouse embryos in this respect. Rabbit epiblasts resemble the flat blastodisc of chicken and human embryos. Page reference: 120 Type: multiple choice question Title: Chapter 03 - Question 07 07) Which statement is not true of human embryonic development? a. Human fertilization takes place within the Fallopian tube. Feedback: No, this is true. Human fertilization takes place within the Fallopian tube. Cleavage events proceed as the embryo migrates toward the uterus. Page reference: 131 b. Human embryonic cells undergo compaction. Feedback: No, this is true. Human embryos are similar to mouse embryos in this respect. Compaction forms a solid ball called a morula, in which individual cell outlines can no longer be discerned. Page reference: 132 c. Human embryos develop a primitive streak. Feedback: No, this is true. Human embryos are no different from mouse and chick embryos in that a primitive streak forms within the epiblast and is the site of cellular ingression to give rise to the endoderm and mesoderm. Page reference: 132 *d. Human embryos undergo a “turning” step. Feedback: No, this is not true. Human embryos are unlike mouse embryos in this respect. Unlike the mouse embryo, the human embryo positions its dorsal surface on the outside and is surrounded by its extra-embryonic membranes from the beginning. Page reference: 133–134 Type: multiple choice question Title: Chapter 03 - Question 08 08) Which statement is not true of RNA seq? *a. It is less accurate than microarrays. Feedback: This is not true. RNA seq is more accurate because it involves direct sequencing of mRNA constructs. These sequences are mapped to a reference genome and their density is used to determine the level of gene expression. Page reference: 117 b. It can identify the expression of large numbers of genes at the same time. Feedback: This is true. RNA seq is becoming widely used for determining all of the genes expressed in a particular tissue or at a particular stage of development. Page reference: 117 c. It can determine the changes in gene expression during development. Feedback: This is true. Just like microarrays, RNA seq can be used to sequence large groups of mRNA sequences at different developmental time points. This provides information on gene expression changes as development proceeds. Page reference: 117

Wolpert et al, Principles of Development 6e Test bank d. It requires direct sequencing of nucleic acids. Feedback: This is true. RNA seq is becoming widely used for determining all of the genes expressed in a particular tissue or at a particular stage of development. It involves direct sequencing of mRNA constructs. These sequences are mapped to a reference genome and their density is used to determine the level of gene expression. Page reference: 117 Type: multiple choice question Title: Chapter 03 - Question 09 09) Which of these techniques is not an example of reverse genetics? a. TILLING. Feedback: No, this is an example of reverse genetics. Reverse genetics involves determining a gene’s function by altering its sequence in a targeted way. Although TILLING uses random mutagenesis, a classical forward genetics approach, it screens for animals that have lesions in a specific gene of interest. Page reference: 123 b. Gene knock-out using homologous recombination Feedback: No, this is an example of reverse genetics. Homologous recombination requires knowing the genomic sequence near or within the gene of interest. Page reference: 127 c. Morpholino antisense RNAs Feedback: No, this is an example of reverse genetics. Morpholinos are stable RNAs designed to be complementary to a specific mRNA. When introduced into a cell, they hybridize to and prevent translation of the target mRNA. Page reference: 125 *d. Mutagenesis screens to uncover developmental mutants. Feedback: Yes, this is not an example of reverse genetics. Indeed, it is an example of forward genetics, as the approach aims to identify mutant phenotypes first. Further genetic approaches are used to determine the abnormal gene responsible for this developmental phenotype. Page reference: 122 Type: multiple choice question Title: Chapter 03 - Question 10 10) With which animal is fate mapping using quail cells associated? a. Zebrafish Feedback: No, transplanted quail cells can be distinguished from chick cells by observing differences in nucleolus staining. Because quail and chick embryos develop similarly, quail cells can be followed in chick fate-mapping experiments. Page reference: 119 b. Mouse Feedback: No, transplanted quail cells can be distinguished from chick cells by observing differences in nucleolus staining. Because quail and chick embryos develop similarly, quail cells can be followed in chick fate-mapping experiments. Page reference: 119 *c. Chick Feedback: Yes, transplanted quail cells can be distinguished from chick cells by observing differences in nucleolus staining. Because quail and chick embryos develop similarly, quail cells can be followed in chick fate-mapping experiments. Page reference: 119 d. Frog Feedback: No, transplanted quail cells can be distinguished from chick cells by observing differences in nucleolus staining. Because quail and chick embryos develop similarly, quail cells can be followed in chick fate-mapping experiments. Page reference: 119

Wolpert et al, Principles of Development 6e Test bank

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 04 - Question 01 01) The amphibian egg is radially symmetric along the animal-vegetal axis. What “breaks” this symmetry? a. Localization of maternal RNAs to the vegetal pole Feedback: No, localization of maternal RNAs will contribute to the animal-vegetal axis. However, fertilization can take place within any region of the animal pole and will initiate a series of events that defines the future dorso-ventral axis. Page reference: 148 *b. Fertilization Feedback: Yes, fertilization can take place within any region of the animal pole and will initiate a series of events that defines the future dorso-ventral axis. Page reference: 148 c. Localization of maternal RNAs to the animal pole Feedback: No, localization of maternal RNAs will contribute to the animal-vegetal axis. However, fertilization can take place within any region of the animal pole and will initiate a series of events that defines the future dorso-ventral axis. Page reference: 148 d. Cleavage Feedback: No, fertilization can take place within any region of the animal pole and will initiate a series of events that defines the future dorso-ventral axis. Page reference: 148 Type: multiple choice question Title: Chapter 04 - Question 02 02) Removing the ventral blastomeres from a four-cell amphibian embryo gives rise to an embryo lacking which tissue? a. Notochord Feedback: No, the two dorsal blastomeres of a divided four-cell amphibian embryo give rise to embryos containing dorsal structures but lacking some ventral structures. The notochord is a dorsal structure and is present in these embryos. Page reference: 149 b. Neural tube Feedback: No, the two dorsal blastomeres of a divided four-cell amphibian embryo give rise to embryos containing dorsal structures but lacking some ventral structures. The neural tube is a dorsal structure and is present in these embryos. Page reference: 149 c. Somites Feedback: No, the two dorsal blastomeres of a divided four-cell amphibian embryo give rise to embryos containing dorsal structures but lacking some ventral structures. Somites are dorsal structures and are present in these embryos. Page reference: 149 *d. Gut Feedback: Yes, the two dorsal blastomeres of a divided four-cell amphibian embryo give rise to embryos containing dorsal structures but lacking some ventral structures. The gut is a ventral structure and is absent in these embryos. Page reference: 149 Type: multiple choice question Title: Chapter 04 - Question 03 03) What is the dorsal vegetal region that induces the Spemann-Mangold organizer in an amphibian embryo? a. Animal cap

Wolpert et al, Principles of Development 6e Test bank Feedback: No, the Nieuwkoop center, named after Pieter Nieuwkoop, resides in a subset of vegetal cells. It sends dorsalizing and mesoderm-inducing signals to cells above to establish the organizer. Page reference: 150 *b. Nieuwkoop center Feedback: Yes, the Nieuwkoop center, named after Pieter Nieuwkoop, resides in a subset of vegetal cells. It sends dorsalizing and mesoderm-inducing signals to cells above to establish the organizer. Page reference: 150 c. Marginal zone Feedback: No, the marginal zone is a belt-like region around the equator of the blastula from which the mesoderm is derived. The Nieuwkoop center, named after Pieter Nieuwkoop, resides in a subset of vegetal cells. It sends dorsalizing and mesoderm-inducing signals to cells above to establish the organizer. Page reference: 150 d. Vegetal center Feedback: No, the Nieuwkoop center, named after Pieter Nieuwkoop, resides in a subset of vegetal cells. It sends dorsalizing and mesoderm-inducing signals to cells above to establish the organizer. Page reference: 150 Type: multiple choice question Title: Chapter 04 - Question 04 04) Which of the options given would not be an expected way of forcing premature onset of the mid-blastula transition? a. Injecting extra DNA into the egg Feedback: No, this would force premature onset of the mid-blastula transition. The onset appears to be dictated by a critical ratio of DNA to cytoplasm. Extra DNA or lower amounts of cytoplasm have been shown to induce premature onset. Page reference: 157 *b. Injecting extra cytoplasm into the egg Feedback: Yes, this would not force premature onset of the mid-blastula transition. Instead, this would delay the onset. The onset appears to be dictated by a critical ratio of DNA to cytoplasm. Extra DNA or lower amounts of cytoplasm have been shown to induce premature onset. Page reference: 157 c. Forcing two sperm to enter the egg Feedback: No, this would force premature onset of the mid-blastula transition. The onset appears to be dictated by a critical ratio of DNA to cytoplasm. Extra DNA or lower amounts of cytoplasm have been shown to induce premature onset. Page reference: 157 d. Removing some cytoplasm from the egg Feedback: No, this would force premature onset of the mid-blastula transition. The onset appears to be dictated by a critical ratio of DNA to cytoplasm. Extra DNA or lower amounts of cytoplasm have been shown to induce premature onset. Page reference: 157 Type: multiple choice question Title: Chapter 04 - Question 05 05) Which of the following does not send signals that directly induce and pattern the mesoderm? a. Vegetal blastomeres Feedback: No, vegetal cells have an important role by sending induction signals to the overlying animal blastomeres to direct them to become mesoderm. Page reference: 159 *b. Animal blastomeres

Wolpert et al, Principles of Development 6e Test bank Feedback: Yes, animal blastomeres do not provide signals that directly induce or pattern the band of mesoderm. Page reference: 159 c. Dorsal mesoderm Feedback: No, dorsal mesoderm has an important role by sending patterning signals that inhibit the range of pro-ventral mesoderm signals emanating from the ventral mesoderm. Page reference: 159 d. Ventral mesoderm Feedback: No, ventral mesoderm has an important role by sending patterning signals across the band of mesoderm to induce a ventral mesoderm-like character. Page reference: 159 Type: multiple choice question Title: Chapter 04 - Question 06 06) Which of the following is not true of the role of BMPs in mesoderm patterning? a. Overexpression of BMPs ventralizes the embryo Feedback: No, this is true. BMP activity is highest on the ventral side of the embryo. Secreted factors emanating from the organizer inhibit BMP activity to induce dorsal structure development. Overexpression of BMPs is expected to artificially overcome the effects of organizer signals. Page reference: 165 *b. Introduction of a dominant-negative BMP receptor ventralizes the embryo. Feedback: Yes, this is not true. Dominant-negative BMP receptor introduction has been shown to dorsalize the embryo such that ventral cells inappropriately develop muscle and notochord. Dominant-negative receptors block BMP transduction and thus mimic secreted factors emanating from the organizer to induce dorsal structure development. Page reference: 165 c. BMP function is inhibited by organizer signals Feedback: No, this is true. Secreted factors emanating from the organizer inhibit BMP activity to induce dorsal structure development. Page reference: 165 d. BMPs are signaling ligands that bind to cell-surface receptors on target cells. Feedback: No, this is true. BMPs are proteins that bind to cell-surface receptors to induce changes within target cells. Dominant-negative receptor introduction has been shown to dorsalize the embryo such that ventral cells inappropriately develop muscle and notochord. Dominant-negative receptors block BMP transduction and thus mimic secreted factors emanating from the organizer to induce dorsal structure development. Page reference: 165 Type: multiple choice question Title: Chapter 04 - Question 07 07) Which of the following is the only structure induced If one performs the organizer transplantation experiment with a blastopore lip from a late stage gastrula? a. Head Feedback: No, as gastrulation proceeds, the inductive properties of the organizer change. Due to the involution of cells past the blastopore, the cellular make-up of the dorsal blastopore lip is not uniform and instead changes over time. Page reference: 167 b. Trunk Feedback: No, as gastrulation proceeds, the inductive properties of the organizer change. Due to the involution of cells past the blastopore, the cellular make-up of the dorsal blastopore lip is not uniform and instead changes over time. Page reference: 167 *c. Tail

Wolpert et al, Principles of Development 6e Test bank Feedback: Yes, as gastrulation proceeds, the inductive properties of the organizer change. Due to the involution of cells past the blastopore, the cellular make-up of the dorsal blastopore lip is not uniform and instead changes over time. Page reference: 167 d. Brain Feedback: No, as gastrulation proceeds, the inductive properties of the organizer change. Due to the involution of cells past the blastopore, the cellular make-up of the dorsal blastopore lip is not uniform and instead changes over time. Page reference: 167 Type: multiple choice question Title: Chapter 04 - Question 08 08) Which of the following is not a secreted organizer protein? a. Chordin Feedback: No, chordin is a BMP inhibitor secreted by the organizer Page reference: 165 b. Noggin Feedback: No, noggin is a BMP inhibitor secreted by the organizer Page reference: 165 c. Follistatin Feedback: No, follistatin is a BMP inhibitor secreted by the organizer Page reference: 165 *d. BMP Feedback: Yes, BMP activity is produced in the ventral mesoderm and has opposing effects to the signal proteins secreted by the organizer. The organizer secretes inhibitors of BMP signaling. Page reference: 165 Type: multiple choice question Title: Chapter 04 - Question 09 09) Transplanting a piece of anterior mesoderm to the blastocoel of a host frog embryo will induce which of the following structures? *a. Head Feedback: Yes, the anterior-posterior axis of the nervous system is patterned by the mesoderm. Anterior mesoderm lies underneath the ectoderm and will induce anterior structures, such as the head and brain. Page reference: 171 b. Trunk Feedback: No, the anterior-posterior axis of the nervous system is patterned by the mesoderm. Anterior mesoderm lies underneath the ectoderm and will induce anterior structures, such as the head and brain. More posterior mesoderm induces trunk and tail structures. Page reference: 171 c. Tail Feedback: No, the anterior-posterior axis of the nervous system is patterned by the mesoderm. Anterior mesoderm lies underneath the ectoderm and will induce anterior structures, such as the head and brain. More posterior mesoderm induces trunk and tail structures. Page reference: 171 d. Spinal cord Feedback: No, the anterior-posterior axis of the nervous system is patterned by the mesoderm. Anterior mesoderm lies underneath the ectoderm and will induce anterior structures, such as the head and brain. More posterior mesoderm induces trunk and tail structures. Page reference: 171 Type: multiple choice question Title: Chapter 04 - Question 10

Wolpert et al, Principles of Development 6e Test bank 10) In the zebrafish embryo, what is the equivalent of the Xenopus organizer? *a. Shield Feedback: Yes, the shield is able to induce a complete body axis if transplanted to another embryo. Page reference: 174 b. Node Feedback: No, the shield is able to induce a complete body axis if transplanted to another embryo. Page reference: 174 c. Blastopore lip Feedback: No, the shield is able to induce a complete body axis if transplanted to another embryo. Page reference: 174 d. Plate Feedback: No, the shield is able to induce a complete body axis if transplanted to another embryo. Page reference: 174

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 05 - Question 01 01) What determines the orientation of the antero-posterior axis in the epiblast of a chick embryo? a. A random process Feedback: No, as the egg rolls down the uterus it rotates around its long axis. Gravity repositions materials in the yolk. The lowermost edge of the blastoderm becomes the future anterior end of the embryo. The uppermost edge of the blastoderm becomes the posterior marginal zone. Page reference: 188 b. Interaction with the surrounding albumin Feedback: Yes, as the egg rolls down the uterus it rotates around its long axis. Gravity repositions materials in the yolk. The lowermost edge of the blastoderm becomes the future anterior end of the embryo. The uppermost edge of the blastoderm becomes the posterior marginal zone. Page reference: 188 *c. Gravity effects on the embryo Feedback: Yes, as the egg rolls down the uterus it rotates around its long axis. Gravity repositions materials in the yolk. The lowermost edge of the blastoderm becomes the future anterior end of the embryo. The uppermost edge of the blastoderm becomes the posterior marginal zone. Page reference: 188 d. It is oriented away from the site of sperm entry Feedback: No, as the egg rolls down the uterus it rotates around its long axis. Gravity repositions materials in the yolk. The lowermost edge of the blastoderm becomes the future anterior end of the embryo. The uppermost edge of the blastoderm becomes the posterior marginal zone. Page reference: 188 Type: multiple choice question Title: Chapter 05 - Question 02 02) Which of the options given is the Nieuwkoop center analog in the chick embryo? a. Anterior marginal zone Feedback: No, the posterior marginal zone can induce the formation of a new body axis when grafted to another position on a second blastoderm. A new primitive streak, the chick equivalent to the blastopore, is induced in these grafts. Page reference: 187 *b. Posterior marginal zone Feedback: Yes, the posterior marginal zone can induce the formation of a new body axis when grafted to another position on a second blastoderm. A new primitive streak, the chick equivalent to the blastopore, is induced in these grafts. Page reference: 187 c. Area pellucida Feedback: No, the posterior marginal zone can induce the formation of a new body axis when grafted to another position on a second blastoderm. A new primitive streak, the chick equivalent to the blastopore, is induced in these grafts. Page reference: 187 d. Area opaca Feedback: No, the posterior marginal zone can induce the formation of a new body axis when grafted to another position on a second blastoderm. A new primitive streak, the chick equivalent to the blastopore, is induced in these grafts. Page reference: 187 Type: multiple choice question Title: Chapter 05 - Question 03

Wolpert et al, Principles of Development 6e Test bank 03) Which of the following is not true of the trophectoderm? a. Cells on the morula’s periphery tend to become trophectoderm Feedback: No, this is true. Fate-mapping experiments at the eight-cell stage in the mouse embryo show that when labeled cells reside on the outside, they tend to become trophectoderm. Cells that reside on the inside tend to become inner cell mass cells. Page reference: 190 b. Formation of the trophectoderm is the first differentiation event in mammalian embryonic development Feedback: No, this is true. The separation of fates between cells of the inner cell mass and the trophectoderm is the first differentiation event in the mammalian embryo. Page reference: 190 *c. The transcription factor Oct4 promotes trophectoderm formation Feedback: Yes, this is not true. Oct4 is a transcription factor required for keeping the inner cell mass pluripotent. Cdx2, another transcription factor, becomes slightly higher in peripheral cells and establishes a mutual inhibitory relationship with Oct4 to repress each other’s expression. Cdx2 expression becomes exclusive to cells fated to become trophectoderm. Page reference: 190 d. Mouse chimeras have been used to study trophectoderm specification Feedback: No, this is true. Fatemapping experiments at the eight-cell stage in the mouse show that when labeled cells reside on the outside, they tend to become trophectoderm. Cells that reside on the inside tend to become inner cell mass cells. Page reference: 190 Type: multiple choice question Title: Chapter 05 - Question 04 04) What is the result of Gata6 expression within the inner cell mass? *a. Cells differentiate into a layer of primitive endoderm Feedback: Yes, following the delineation of inner cell mass from the trophectoderm, inner mass cells begin to express one of two transcription factor genes. Nanog-expressing cells give rise to epiblast, whereas Gata6-expressing cells become primitive endoderm. Page reference: 190 b. Cells differentiate into trophoblasts Feedback: No, following the delineation of inner cell mass from the trophectoderm, inner mass cells begin to express one of two transcription factor genes. Nanog-expressing cells give rise to epiblast, whereas Gata6-expressing cells become primitive endoderm. Page reference: 190 c. Cells differentiate into epiblast Feedback: Yes, following the delineation of inner cell mass from the trophectoderm, inner mass cells begin to express one of two transcription factor genes. Nanog-expressing cells give rise to epiblast, whereas Gata6-expressing cells become primitive endoderm. Page reference: 190 d. Cells revert back to a more pluripotent state Feedback: No, following the delineation of inner cell mass from the trophectoderm, inner mass cells begin to express one of two transcription factor genes. Nanog-expressing cells give rise to epiblast, whereas Gata6-expressing cells become primitive endoderm. Page reference: 190 Type: multiple choice question Title: Chapter 05 - Question 05 05) What is another way of referring to the paraxial mesoderm? a. Intermediate mesoderm Feedback: No, the paraxial mesoderm runs alongside the midline adjacent to the neural tube and becomes segmented into individual somites. This is why we often refer to the paraxial mesoderm as the somitic mesoderm.

Wolpert et al, Principles of Development 6e Test bank Page reference: 197 *b. Somitic mesoderm Feedback: Yes, the paraxial mesoderm runs alongside the midline adjacent to the neural tube and becomes segmented into individual somites. This is why we often refer to the paraxial mesoderm as the somitic mesoderm. Page reference: 197 c. Lateral plate mesoderm Feedback: Yes, the paraxial mesoderm runs alongside the midline adjacent to the neural tube and becomes segmented into individual somites. This is why we often refer to the paraxial mesoderm as the somitic mesoderm. Page reference: 197 d. Notochord Feedback: No, the paraxial mesoderm runs alongside the midline adjacent to the neural tube and becomes segmented into individual somites. This is why we often refer to the paraxial mesoderm as the somitic mesoderm. Page reference: 197 Type: multiple choice question Title: Chapter 05 - Question 06 06) What is the signaling protein responsible for initiating neural tissue induction in the chick embryo? *a. FGF Feedback: Yes, FGF signalling is responsible for initiating neural tissue induction prior to inhibition of BMP signaling by BMP antagonists. Page reference: 200 b. BMP Feedback: No, FGF signaling is responsible for initiating neural tissue induction prior to inhibition of BMP signalling by BMP antagonists. Page reference: 200 c. Chordin Feedback: Yes, FGF signaling is responsible for initiating neural tissue induction prior to inhibition of BMP signalling by BMP antagonists. Page reference: 200 d. Cerberus Feedback: No, FGF signaling is responsible for initiating neural tissue induction prior to inhibition of BMP signalling by BMP antagonists. Page reference: 200 Type: multiple choice question Title: Chapter 05 - Question 07 07) Which of the following is not true of somites? a. Somites give rise to bone, cartilage, and muscle of the body axis Feedback: No, this is true. Somites are blocks of tissue that form from the paraxial mesoderm on both sides of the developing neural tube. This occurs simultaneously. They give rise to bone and cartilage of the body axis, and to skeletal muscle. Page reference: 208 b. Two somites form simultaneously Feedback: No, this is true. Somites are blocks of tissue that form from the paraxial mesoderm on both sides of the developing neural tube. This occurs simultaneously. They give rise to bone and cartilage of the body axis, and to skeletal muscle. Page reference: 208 *c. Somites form rhythmically from posterior to anterior Feedback: Yes, this is not true. Somites are formed from the paraxial mesoderm in an anterior to posterior order. Somites are blocks of tissue that form from the paraxial mesoderm on both

Wolpert et al, Principles of Development 6e Test bank sides of the developing neural tube. This occurs simultaneously. They give rise to bone and cartilage of the body axis, and to skeletal muscle. Page reference: 208 d. Somites are formed from mesoderm adjacent to the neural tube Feedback: No, this is true. Somites are blocks of tissue that form from the paraxial mesoderm on both sides of the developing neural tube. This occurs simultaneously. They give rise to bone and cartilage of the body axis, and to skeletal muscle. Page reference: 208 Type: multiple choice question Title: Chapter 05 - Question 08 08) What does the “clock and wavefront” model propose? a. Cells must undergo a specific number of oscillations of gene activity in order to form a somite Feedback: No, the model suggests that as gene expression within cells in the pre-somitic mesoderm oscillates, cells only react to a burst of clock gene activity after they have been passed by the determination wavefront. Page reference: 212 *b. Cells must be passed by the wavefront to commit to forming a somite Feedback: Yes, the model suggests that as gene expression within cells in the pre-somitic mesoderm oscillates, cells only react to a burst of clock gene activity after they have been passed by the determination wavefront. Page reference: 212 c. Cells must not have yet been passed by the wavefront to commit to forming a somite Feedback: No, the model suggests that as gene expression within cells in the pre-somitic mesoderm oscillates, cells only react to a burst of clock gene activity after they have been passed by the determination wavefront. Page reference: 212 d. Genes that position a wavefront have clock-like gene expression Feedback: No, the model suggests that as gene expression within cells in the pre-somitic mesoderm oscillates, cells only react to a burst of clock gene activity after they have been passed by the determination wavefront. Page reference: 212 Type: multiple choice question Title: Chapter 05 - Question 09 09) Which of the following genes determines the identity of somites in mouse and chick embryos and can be disrupted in order to induce transformations or antero-posterior shifts in vertebral fate? *a. Hox Feedback: Yes, just as in the fly, Hox genes show co-linearity in vertebrate embryos, and in vertebrates determine the identity of vertebral bones along the antero-posterior axis. Shifts in Hox gene activity, whether through deletion or overexpression, can have a drastic effect on the types of vertebral bones at antero-posterior positions. Page reference: 215 b. BMP Feedback: No, just as in the fly, Hox genes show co-linearity in vertebrate embryos, and in vertebrates determine the identity of vertebral bones along the antero-posterior axis. Shifts in Hox gene activity, whether through deletion or overexpression, can have a drastic effect on the types of vertebral bones at antero-posterior positions. Page reference: 215 c. Fgf Feedback: No, just as in the fly, Hox genes show co-linearity in vertebrate embryos, and in vertebrates determine the identity of vertebral bones along the antero-posterior axis. Shifts in

Wolpert et al, Principles of Development 6e Test bank Hox gene activity, whether through deletion or overexpression, can have a drastic effect on the types of vertebral bones at antero-posterior positions. Page reference: 215 d. Notch Feedback: No, just as in the fly, Hox genes show co-linearity in vertebrate embryos, and in vertebrates determine the identity of vertebral bones along the antero-posterior axis. Shifts in Hox gene activity, whether through deletion or overexpression, can have a drastic effect on the types of vertebral bones at antero-posterior positions. Page reference: 215 Type: multiple choice question Title: Chapter 05 - Question 10 10) The sclerotome region of a somite gives rise to vertebrae and ribs. From which tissues does the sclerotome receive signals to direct these fates? a. Lateral plate mesoderm Feedback: No, different regions of a developing somite receive molecular signals form nearby tissues. The sclerotome is the region of a developing somite nearest the notochord and floor plate. Sonic hedgehog, emanating from both of these regions, directs nearby sclerotome cells to condense around the notochord and neural tube to form the vertebrae and ribs. Page reference: 224 *b. Notochord and floor plate Feedback: Yes, different regions of a developing somite receive molecular signals form nearby tissues. The sclerotome is the region of a developing somite nearest the notochord and floor plate. Sonic hedgehog, emanating from both of these regions, directs nearby sclerotome cells to condense around the notochord and neural tube to form the vertebrae and ribs. Page reference: 224 c. Roof plate and overlying ectoderm Feedback: No, different regions of a developing somite receive molecular signals form nearby tissues. The sclerotome is the region of a developing somite nearest the notochord and floor plate. Sonic hedgehog, emanating from both of these regions, directs nearby sclerotome cells to condense around the notochord and neural tube to form the vertebrae and ribs. Page reference: 224 d. Endoderm Feedback: No, different regions of a developing somite receive molecular signals form nearby tissues. The sclerotome is the region of a developing somite nearest the notochord and floor plate. Sonic hedgehog, emanating from both of these regions, directs nearby sclerotome cells to condense around the notochord and neural tube to form the vertebrae and ribs. Page reference: 224

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 06 - Question 01 01) In C. elegans more cells are initially formed than survive. What is the mechanism by which the cell number decreases? a. Necrosis Feedback: No, a subset of cells originally produced is targeted for apoptosis, or programmed cell death. During apoptosis, chromatin is fragmented and the cytoplasm shrinks and breaks up. Apoptosis is an orchestrated event that bypasses the cytotoxic effects on neighbouring cells that results from necrosis. Page reference: 239 b. Asymmetric cell division Feedback: No, a subset of cells originally produced is targeted for apoptosis, or programmed cell death. During apoptosis, chromatin is fragmented and the cytoplasm shrinks and breaks up. Apoptosis is an orchestrated event that bypasses the cytotoxic effects on neighbouring cells that results from necrosis. Page reference: 239 *c. Apoptosis Feedback: Yes, a subset of cells originally produced is targeted for apoptosis, or programmed cell death. During apoptosis, chromatin is fragmented and the cytoplasm shrinks and breaks up. Apoptosis is an orchestrated event that bypasses the cytotoxic effects on neighbouring cells that results from necrosis. Page reference: 239 d. Programmed cleavage Feedback: No, a subset of cells originally produced is targeted for apoptosis, or programmed cell death. During apoptosis, chromatin is fragmented and the cytoplasm shrinks and breaks up. Apoptosis is an orchestrated event that bypasses the cytotoxic effects on neighbouring cells that results from necrosis. Page reference: 239 Type: multiple choice question Title: Chapter 06 - Question 02 02) Which of the following is not true of the first cleavage event in C. elegans? *a. It establishes the dorso-ventral axis Feedback: Yes, this is not true. Sperm entry determines the plane of the first cleavage event. The first cleavage event is asymmetric and occurs within the plane of the future antero-posterior axis to give rise to two unequally sized daughter cells. Each anterior and posterior cell will go on to define its own lineages. Page reference: 241 b. It is asymmetric giving rise two daughter cells of different sizes Feedback: No, this is true. Sperm entry determines the plane of the first cleavage event. The first cleavage event is asymmetric and occurs within the plane of the future antero-posterior axis to give rise to two unequally sized daughter cells. Each anterior and posterior cell will go on to define its own lineages. Page reference: 241 c. It establishes the antero-posterior axis Feedback: No, this is true. Sperm entry determines the plane of the first cleavage event. The first cleavage event is asymmetric and occurs within the plane of the future antero-posterior axis to give rise to two unequally sized daughter cells. Each anterior and posterior cell will go on to define its own lineages. Page reference: 241 d. Its orientation is determined by the point of sperm entry Feedback: No, this is true. Sperm entry determines the plane of the first cleavage event. The first cleavage event is asymmetric and occurs within the plane of the future antero-posterior axis

Wolpert et al, Principles of Development 6e Test bank to give rise to two unequally sized daughter cells. Each anterior and posterior cell will go on to define its own lineages. Page reference: 241 Type: multiple choice question Title: Chapter 06 - Question 03 03) What are the key molecular regulators of asymmetric cell division in the early C. elegans embryo? *a. Partition proteins Feedback: Yes, partition proteins, or Par proteins, are maternal proteins that become localized to anterior or posterior cortical regions. Par proteins control asymmetric cell divisions in the early embryo by correctly positioning and orienting the mitotic spindles. Although P granules become asymmetrically localized, they are not determinants of asymmetry. Page reference: 244 b. Polarizing proteins Feedback: No, partition proteins, or Par proteins, are maternal proteins that become localized to anterior or posterior cortical regions. Par proteins control asymmetric cell divisions in the early embryo by correctly positioning and orienting the mitotic spindles. Although P granules become asymmetrically localized, they are not determinants of asymmetry. Page reference: 244 c. Asymmetrins Feedback: No, partition proteins, or Par proteins, are maternal proteins that become localized to anterior or posterior cortical regions. Par proteins control asymmetric cell divisions in the early embryo by correctly positioning and orienting the mitotic spindles. Although P granules become asymmetrically localized, they are not determinants of asymmetry. Page reference: 244 d. P granules Feedback: No, partition proteins, or Par proteins, are maternal proteins that become localized to anterior or posterior cortical regions. Par proteins control asymmetric cell divisions in the early embryo by correctly positioning and orienting the mitotic spindles. Although P granules become asymmetrically localized, they are not determinants of asymmetry. Page reference: 244 Type: multiple choice question Title: Chapter 06 - Question 04 04) What class of genetic mutations produce alterations in the timing of developmental events? *a. Heterochronic Feedback: Yes, heterochronic mutants, produce retarded or precocious development. Page reference: 250 b. Homochronic Feedback: No, heterochronic mutants, produce retarded or precocious development. Page reference: 250 c. Periodic Feedback: No, heterochronic mutants, produce retarded or precocious development. Page reference: 250 d. Cyclic Feedback: No, heterochronic mutants, produce retarded or precocious development. Page reference: 250 Type: multiple choice question Title: Chapter 06 - Question 05 05) Which of the following is not true of C. elegans vulval development? a. The anchor cell sends inductive signals to vulval precursors

Wolpert et al, Principles of Development 6e Test bank Feedback: No, this is true. The anchor cell sends signals to the EGFR on neighbouring cells to induce their fate. Cells receiving highest signal adopt a primary fate with adjacent cells adopting a secondary fate. The primary cell inhibits adjacent cells from also adopting a primary fate. Page reference: 253 b. Primary vulval precursors receive higher levels of inductive signals than secondary precursors Feedback: No, this is true. The anchor cell sends signals to the EGFR on neighbouring cells to induce their fate. Cells receiving highest signal adopt a primary fate with adjacent cells adopting a secondary fate. The primary cell inhibits adjacent cells from also adopting a primary fate. Page reference: 253 *c. Anchor cells become primary vulval precursors Feedback: Yes, this is not true. The anchor cell sends signals to the EGFR on neighbouring cells to induce their fate. Cells receiving highest signal adopt a primary fate with adjacent cells adopting a secondary fate. The primary cell inhibits adjacent cells from also adopting a primary fate. Page reference: 253 d. Primary vulval precursors inhibit a similar fate in neighboring cells Feedback: No, this is true. The anchor cell sends signals to the EGFR on neighboring cells to induce their fate. Cells receiving highest signal adopt a primary fate with adjacent cells adopting a secondary fate. The primary cell inhibits adjacent cells from also adopting a primary fate. Page reference: 253 Type: multiple choice question Title: Chapter 06 - Question 06 06) What is the result of separating and isolating each cell of a four-cell sea urchin embryo? *a. Each blastomere becomes a small larvae Feedback: Yes, the four-cell sea urchin embryo exhibits a great deal of regulation as development proceeds normally in isolated blastomeres. This is due to the fact that the animal and vegetal halves have not been separated under these conditions. However, animal and vegetal blastomeres isolated at the eight-cell stage give rise to abnormal animalized and vegetalized embryos, respectively. Page reference: 259 b. Each blastomere becomes an animalized ciliated sphere of ectoderm Feedback: No, the four-cell stage sea urchin embryo exhibits a great deal of regulation as development proceeds normally in isolated blastomeres. This is due to the fact that the animal and vegetal halves have not been separated under these conditions. However, isolated the animal and vegetal blastomeres at the eight-cell stage gives rise to abnormal animalized and vegetalized embryos, respectively. Page reference: 259 c. Each blastomere becomes a vegetalized abnormal embryo with a pronounced gut Feedback: No, the four-cell stage sea urchin embryo exhibits a great deal of regulation as development proceeds normally in isolated blastomeres. This is due to the fact that the animal and vegetal halves have not been separated under these conditions. However, isolated the animal and vegetal blastomeres at the eight-cell stage gives rise to abnormal animalized and vegetalized embryos, respectively. Page reference: 259 d. Each blastomere dies shortly after isolation. Feedback: No, the four-cell stage sea urchin embryo exhibits a great deal of regulation as development proceeds normally in isolated blastomeres. This is due to the fact that the animal and vegetal halves have not been separated under these conditions. However, isolated the animal and vegetal blastomeres at the eight-cell stage gives rise to abnormal animalized and vegetalized embryos, respectively. Page reference: 259 Type: multiple choice question

Wolpert et al, Principles of Development 6e Test bank Title: Chapter 06 - Question 07 07) Echinoderms are similar to vertebrates in that they both develop from embryos where primary invagination of the gut forms the anus, with the mouth developing subsequently. In which group are echinoderms classified? a. Protostome Feedback: No, the group of animals whose embryos form the anus first from the primary invagination while forming the mouth subsequently are referred to as deuterostomes. Protostomes are different in that they form the mouth (stoma) first (proto) from the primary invagination. Page reference: 256 b. Duostome Feedback: No, the group of animals whose embryos form the anus first from the primary invagination while forming the mouth subsequently are referred to as deuterostomes. Protostomes are different in that they form the mouth (stoma) first (proto) from the primary invagination. Page reference: 256 *c. Deuterostome Feedback: Yes, the group of animals whose embryos form the anus first from the primary invagination while forming the mouth subsequently are referred to as deuterostomes. Protostomes are different in that they form the mouth (stoma) first (proto) from the primary invagination. Page reference: 256 d. Proctostome Feedback: No, the group of animals whose embryos form the anus first from the primary invagination while forming the mouth subsequently are referred to as deuterostomes. Protostomes are different in that they form the mouth (stoma) first (proto) from the primary invagination. Page reference: 256 Type: multiple choice question Title: Chapter 06 - Question 08 08) What is the result of grafting micromeres to the side of an intact sea urchin embryo? a. Endoderm development was inhibited and no gut formation takes place Feedback: No, micromeres exhibit some organizer activity. When transplanted to the side of an intact embryo, a region of endoderm is induced within the ectoderm that invaginates to form a second gut. Page reference: 261 *b. A region of endoderm is induced that invaginates to form a second gut. Feedback: Yes, micromeres exhibit some organizer activity. When transplanted to the side of an intact embryo, a region of endoderm is induced within the ectoderm that invaginates to form a second gut. Page reference: 261 c. The micromeres receive signals from the embryo to develop into endoderm Feedback: No, micromeres exhibit some organizer activity. When transplanted to the side of an intact embryo, a region of endoderm is induced within the ectoderm that invaginates to form a second gut. Page reference: 261 d. The micromeres have no effect on the embryo and instead under apoptosis Feedback: No, micromeres exhibit some organizer activity. When transplanted to the side of an intact embryo, a region of endoderm is induced within the ectoderm that invaginates to form a second gut. Page reference: 261 Type: multiple choice question

Wolpert et al, Principles of Development 6e Test bank Title: Chapter 06 - Question 09 09) What is the result of combining micromeres and the animal half of a 32-cell embryo? a. A region of endoderm is induced that invaginates to form a second gut. Feedback: No, micromeres exhibit some organizer activity. When combined with the animal half of a 32-cell embryo, micromeres signal to animal cells and direct normal development. Page reference: 261 b. Endoderm development was inhibited and no gut formation takes place Feedback: No, micromeres exhibit some organizer activity. When combined with the animal half of a 32-cell embryo, micromeres signal to animal cells and direct normal development. Page reference: 261 c. The micromeres receive signals from the embryo to develop into endoderm Feedback: No, micromeres exhibit some organizer activity. When combined with the animal half of a 32-cell embryo, micromeres signal to animal cells and direct normal development. Page reference: 261 *d. A normal larva develops. Feedback: Yes, micromeres exhibit some organizer activity. When combined with the animal half of a 32-cell embryo, micromeres signal to animal cells and direct normal development. Page reference: 261 Type: multiple choice question Title: Chapter 06 - Question 10 10) Which of the following acts as a transcriptional co-activator within micromeres to specify vegetal fate? *a. Beta-catenin Feedback: Yes, beta-catenin is the transcriptional co-activator of the Wnt signaling pathway. Experimental manipulations leading to the accumulation of beta-catenin or an increase in its activity gives rise to vegetalized embryos with a reduced ectoderm and expanded endoderm with an enlarged gut. Page reference: 262 b. Wnt Feedback: No, Wnt is the signaling ligand of the Wnt pathway. However, beta-catenin is the transcriptional co-activator of the Wnt signaling pathway. Experimental manipulations leading to the accumulation of beta-catenin or an increase in its activity gives rise to vegetalized embryos with a reduced ectoderm and expanded endoderm with an enlarged gut. Page reference: 262 c. Dishevelled Feedback: No, Dishevelled has an integral role in transducing Wnt signals. However, betacatenin is the transcriptional co-activator of the Wnt signaling pathway. Experimental manipulations leading to the accumulation of beta-catenin or an increase in its activity gives rise to vegetalized embryos with a reduced ectoderm and expanded endoderm with an enlarged gut. Page reference: 262 d. Frizzled Feedback: No, Frizzled is the Wnt receptor and has an integral role in transducing Wnt signals. However, beta-catenin is the transcriptional co-activator of the Wnt signaling pathway. Experimental manipulations leading to the accumulation of beta-catenin or an increase in its activity gives rise to vegetalized embryos with a reduced ectoderm and expanded endoderm with an enlarged gut. Page reference: 262

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 07 - Question 01 01) What is the family of cell-adhesion molecules that require calcium to adhere to the same molecules on another cell? *a. Cadherins Feedback: Yes, cadherins are cell-adhesion molecules on the surface of cells that bind to other cadherins on the surface of other cells in a calcium-dependant manner. Page reference: 276 b. CAMs Feedback: No, cadherins are cell-adhesion molecules on the surface of cells that bind to other cadherins on the surface of other cells in a calcium-dependant manner. CAMs are calciumindependent cell adhesion molecules. Page reference: 276 c. Integrins Feedback: Yes, cadherins are cell-adhesion molecules on the surface of cells that bind to other cadherins on the surface of other cells in a calcium-dependant manner. Integrins bind to molecules in the extracellular matrix, thus forming interactions between the cell and its substratum. Page reference: 276 d. Laminins Feedback: No, cadherins are cell-adhesion molecules on the surface of cells that bind to other cadherins on the surface of other cells in a calcium-dependant manner. Laminins are extracellular matrix proteins that interact with cell-surface integrins. Page reference: 276 Type: multiple choice question Title: Chapter 07 - Question 02 02) Which of the following is not associated with the differential adhesion hypothesis? a. Cells sort according to differences in adhesiveness and surface tension Feedback: No, this is associated with the differential adhesion hypothesis. It assumes cellular populations maintain different surface tensions and adhesiveness properties that cause cell sorting to occur. Therefore, it assumes cells interact similarly to molecules within two immiscible liquids. Page reference: 276–277 b. Cells sort similarly to molecules of two immiscible liquids Feedback: No, this is associated with the differential adhesion hypothesis. It assumes cellular populations maintain different surface tensions and adhesiveness properties that cause cell sorting to occur. Therefore, it assumes cells interact similarly to molecules within two immiscible liquids. Page reference: 276–277 c. Cells sort according to the types and numbers of cell-adhesion molecules Feedback: No, this is associated with the differential adhesion hypothesis. It assumes cellular populations maintain different surface tensions and adhesiveness properties that cause cell sorting to occur. Therefore, it assumes cells interact similarly to molecules within two immiscible liquids. These differences in surface tension and adhesiveness can be established through differences in the types and numbers of cell adhesion molecules between sorting cell populations. Page reference: 276–277 *d. Cell sorting recapitulates the final positions of cell layers in the normal embryo. Feedback: Yes, this is not associated with the differential adhesion hypothesis. Although some isolated and mixed germ layers sort out from each other in ways that seem to mimic their final position in a normal embryo, this is not always accomplished. This is because their final positions are determined by a more complex set of developmental constraints. Page reference: 276–277

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 07 - Question 03 03) Which of these statements is true of cells moving through the primitive streak of a chick or a mouse embryo? *a. Cells become mesenchymal in nature. Feedback: Yes, cells within the epiblast detach from the epithelium and migrate down through the primitive streak and into the interior of the embryo to form the mesoderm and endoderm. During this epithelial-to-mesenchymal transition cells lose their epithelial-like characteristics of being tightly packed together through strong adherens junctions. Instead, cells become mesenchymal in nature, become loosely packed together and weaken adherens junctions. Page reference: 281 b. Cells maintain their epithelial nature. Feedback: No, cells within the epiblast detach from the epithelium and migrate down through the primitive streak and into the interior of the embryo to form the mesoderm and endoderm. During this epithelial-to-mesenchymal transition cells lose their epithelial-like characteristics of being tightly packed together through strong adherens junctions. Instead, cells become mesenchymal in nature, become loosely packed together and weaken adherens junctions. Page reference: 281 c. Cells strengthen adherens junction complexes. Feedback: No, cells within the epiblast detach from the epithelium and migrate down through the primitive streak and into the interior of the embryo to form the mesoderm and endoderm. During this epithelial-to-mesenchymal transition cells lose their epithelial-like characteristics of being tightly packed together through strong adherens junctions. Instead, cells become mesenchymal in nature, become loosely packed together and weaken adherens junctions. Page reference: 281 d. Cells maintain their tightly packed organization. Feedback: No, cells within the epiblast detach from the epithelium and migrate down through the primitive streak and into the interior of the embryo to form the mesoderm and endoderm. During this epithelial-to-mesenchymal transition cells lose their epithelial-like characteristics of being tightly packed together through strong adherens junctions. Instead, cells become mesenchymal in nature, become loosely packed together and weaken adherens junctions. Page reference: 281 Type: multiple choice question Title: Chapter 07 - Question 04 04) The first cleavage event in a C. elegans embryo gives rise to two differently sized cells with different content and fates. What is this type of cell division called? *a. Asymmetric division Feedback: Yes, when cell division occurs to give rise to two daughter cells of (usually) unequal size and different contents, it is said to be asymmetric. Symmetric division gives rise to cells that are equal in size and contain the same content. Page reference: 285 b. Symmetric division Feedback: No, when cell division occurs to give rise to two daughter cells of (usually) unequal size and different contents, it is said to be asymmetric. Symmetric division gives rise to cells that are equal in size and contain the same content. Page reference: 285 c. Radial division Feedback: No, when cell division occurs to give rise to two daughter cells of (usually) unequal size and different contents, it is said to be asymmetric. Symmetric division gives rise to cells that are equal in size and contain the same content. Radial cleavage is a type of cleavage event whereby divisions occur at right angels to the egg surface. Page reference: 285 d. Spiral division

Wolpert et al, Principles of Development 6e Test bank Feedback: No, when cell division occurs to give rise to two daughter cells of (usually) unequal size and different contents, it is said to be asymmetric. Symmetric division gives rise to cells that are equal in size and contain the same content. Spiral cleavage is a type of cleavage event whereby divisions occur at slight angles to each other, producing a spiral arrangement of cells. Page reference: 285 Type: multiple choice question Title: Chapter 07 - Question 05 05) Which of the following does not play a role in the formation of a blastocoel? a. Sodium Feedback: No, sodium does play a role in blastocoel formation. The blastocoel forms when the accumulation of fluid exerts outward pressure on the blastula wall. As tight junctions form a barrier within the outer layer of the morula, membrane transport proteins transport sodium and other electrolytes into the extracellular space. This increase in ion concentration draws water into the blastocoel through osmosis. Page reference: 289–290 b. Osmosis Feedback: No, osmosis does play a role in blastocoel formation. The blastocoel forms when the accumulation of fluid exerts outward pressure on the blastula of blastocyst wall. As tight junctions form a barrier within the outer layer of the morula, membrane transport proteins transport sodium and other electrolytes into the extracellular space. This increase in ion concentration draws water into the blastocoel through osmosis. Page reference: 289–290 c. Tight junctions Feedback: No, tight junctions play a role in blastocoel formation. The blastocoel forms when the accumulation of fluid exerts outward pressure on the blastula of blastocyst wall. As tight junctions form a barrier within the outer layer of the morula, membrane transport proteins transport sodium and other electrolytes into the extracellular space. This increase in ion concentration draws water into the blastocoel through osmosis. Page reference: 289–290 *d. Apoptosis Feedback: Yes, apoptosis does not play a role in blastocoel formation. The blastocoel forms when the accumulation of fluid exerts outward pressure on the blastula of blastocyst wall. As tight junctions form a barrier within the outer layer of the morula, membrane transport proteins transport sodium and other electrolytes into the extracellular space. This increase in ion concentration draws water into the blastocoel through osmosis. Page reference: 289–290 Type: multiple choice question Title: Chapter 07 - Question 06 06) What is the subcellular event that provides the force required for puckering the epithelium during invagination? a. Inhibition of myosin motor activity Feedback: No, contractile actin filaments composed of actin and its motor protein myosin contract at the outer edge of a subset of cells within an epithelium. This contractile force makes them wedge-shaped, thus causing the epithelium in that region to pucker and invaginate. Inhibition of myosin motor activity would prevent this contractile force and prevent invagination. Page reference: 296 b. Activation of Snail protein Feedback: No, contractile actin filaments composed of actin and its motor protein myosin contract at the outer edge of a subset of cells within an epithelium. This contractile force makes them wedge-shaped, thus causing the epithelium in that region to pucker and invaginate. Snail activity leads to E-cadherin inhbition and would be likely to induce an epithelial-to-mesenchymal transition.

Wolpert et al, Principles of Development 6e Test bank Page reference: 296 c. Endocytosis of cadherins Feedback: No, contractile actin filaments composed of actin and its motor protein myosin contract at the outer edge of a subset of cells within an epithelium. This contractile force makes them wedge-shaped, thus causing the epithelium in that region to pucker and invaginate. Endocytosis of E-cadherin would be likely to induce an epithelial-to-mesenchymal transition. Page reference: 296 *d. Asymmetric actin-based contraction Feedback: Yes, contractile actin filaments composed of actin and its motor protein myosin contract at the outer edge of a subset of cells within an epithelium. This contractile force makes them wedge-shaped, thus causing the epithelium in that region to pucker and invaginate. Page reference: 296 Type: multiple choice question Title: Chapter 07 - Question 07 07) Which of the following cell movements involves remodeling of intercellular junctions to guide medio-lateral intercalation? a. Delamination Feedback: No, delamination is the process where cells separate from a continuous sheet of cells. Convergent extension is the type of cell movement whereby cellular intercalation extends an epithelium in one direction when shortening it in another. The intercalation is driven by the disassembly and reassembly of intercellular contacts. Page reference: 304 b. Involution Feedback: No, involution is the rolling-in and underneath of a cellular sheet. Convergent extension is the type of cell movement whereby cellular intercalation extends an epithelium in one direction when shortening it in another. The intercalation is driven by the disassembly and reassembly of intercellular contacts. Page reference: 304 c. Epiboly Feedback: No, epiboly is the spreading and thinning of a cellular sheet. Convergent extension is the type of cell movement whereby cellular intercalation extends an epithelium in one direction when shortening it in another. The intercalation is driven by the disassembly and reassembly of intercellular contacts. Page reference: 304 *d. Convergent extension Feedback: Yes, convergent extension is the type of cell movement whereby cellular intercalation extends an epithelium in one direction when shortening it in another. The intercalation is driven by the disassembly and reassembly of intercellular contacts. Page reference: 304 Type: multiple choice question Title: Chapter 07 - Question 08 08) Which of the following embryonic cell movements involves the separation of cells from a continuous sheet of cells? *a. Ingression Feedback: Yes, cells ingressing through the primitive streak undergo an epithelial-tomesenchymal transition and separate from the continuous sheet of cells (the epiblast). Page reference: 308 b. Involution Feedback: No, involution is the rolling in and under of a cellular sheet. Ingression is the process whereby cells undergo an epithelial-to-mesenchymal transition and separate from the continuous sheet of cells. Page reference: 308

Wolpert et al, Principles of Development 6e Test bank c. Epiboly Feedback: No, epiboly is the spreading and thinning of a cellular sheet. Ingression is the process whereby cells undergo an epithelial-to-mesenchymal transition and separate from the continuous sheet of cells. Page reference: 308 d. Convergent extension Feedback: No, convergent extension is the extension of an epithelium in one direction while shortening it in another. Ingression is the process whereby cells undergo an epithelial-tomesenchymal transition and separate from the continuous sheet of cells. Page reference: 308 Type: multiple choice question Title: Chapter 07 - Question 09 09) What is the ectodermal interface between non-neural ectoderm and the neural plate during neurulation called? *a. Neural fold Feedback: Yes, the neural folds form at the interface between neural plate and non-neural ectoderm. The folding of the neural plate pushes the neural folds toward the midline above the plane of the ectoderm to form a depression called the neural groove between the neural folds. Page reference: 313 b. Neural crest Feedback: No, the neural crest is a population of cells that leaves the dorsal surface of the neural tube on both sides just before and after closure. These cells migrate to different areas of the embryo to form neural crest-derived tissues. The neural folds form at the interface between neural plate and non-neural ectoderm. Page reference: 313 c. Neural furrow Feedback: No, the neural furrow forms by the initial infolding of the neural plate along the midline. The neural folds form at the interface between neural plate and non-neural ectoderm. Page reference: 313 d. Neural groove Feedback: No, the folding of the neural tube pushes the neural folds toward the midline above the plane of the ectoderm to form a depression called the neural groove between the neural folds. The neural folds form at the interface between neural plate and non-neural ectoderm. Page reference: 313 Type: multiple choice question Title: Chapter 07 - Question 10 10) Which of the following results from a failure to close the neural tube in the fore- and midbrain regions? a. Rachischisis Feedback: No, rachischisis is the failure of the spinal cord to close. Anencephaly is the failure to close the neural tube in the fore- and midbrain regions. Page reference: 316 b. Craniorachischisis Feedback: No, craniorachischisis results from the neural tube remaining open from the mid-brain to the lower spine. Anencephaly is the failure to close the neural tube in the fore- and midbrain regions. Page reference: 316 *c. Anencephaly Feedback: Yes, anencephaly is the failure to close the neural tube in the fore- and midbrain regions. Page reference: 316 d. Spina bifida

Wolpert et al, Principles of Development 6e Test bank Feedback: No, spina bifida results from a failure to complete neural tube closure at the posterior neuropore. Anencephaly is the failure to close the neural tube in the fore- and midbrain regions. Page reference: 316

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 08 - Question 01 01) Which of the following is not associated with terminal differentiation? a. Cells assume specific shapes associated with function Feedback: No, this is true. Differentiated cells, such as skeletal muscle and nerve cells, are particularly shaped in order to support their specific functions. These changes in shape are associated with the specific combinations of expressed genes. Page reference: 337 b. It is often controlled by master regulatory genes Feedback: No, this is true. Transcription factors, encoded by master regulatory genes, act in combination to define a particular cell fate. Page reference: 338 *c. Differentiated cells are highly proliferative Feedback: Yes, this is not true. Differentiated cells, such as skeletal muscle or nerve cells, often are post-mitotic and no longer undergo cell division. Page reference: 338 d. Cell fate is controlled by a specific combinations of genes Feedback: No, this is true. Transcription factors, encoded by master regulatory genes, act in combination to define a particular cell fate. Page reference: 338 Type: multiple choice question Title: Chapter 08 - Question 02 02) Which of the following is not true of epigenetic control? a. It hinges on the methylation status of DNA Feedback: No, this is true. DNA methylation has been correlated with the transcriptional silence of a gene. Methylation of a gene’s promoter leads to it being tightly wound around histone proteins, thus preventing transcription of that gene. Page reference: 345 *b. It refers to changes in the DNA nucleotide sequence Feedback: Yes, this is not true. Epigenetics refers to the regulation of gene expression without a modification of the nucleotide sequence of DNA. Page reference: 345 c. It involves post-translational modifications to histone proteins Feedback: No, this is true. Histone proteins are methylated, acetylated, and phosphorylated in order to modify their interactions with DNA. Page reference: 345 d. The pattern of modifications on chromatin can be transmitted to daughter cells. Feedback: No, this is true. During DNA replication, DNA methylase recognizes the methylated cytosines present in a template strand and methylates the corresponding cytosine on the newly synthesized strange. Page reference: 345 Type: multiple choice question Title: Chapter 08 - Question 03 03) What is the correct flow of skeletal muscle development in a vertebrate embryo? *a. Myotome – myoblast – myotube – muscle fiber Feedback: Yes, skeletal muscle cells are derived from the myotome portion of the somite. These somitic cells become myoblasts that differentiate by synthesizing muscle-specific proteins and modifying their shape. These structural changes allow them to fuse to form multinucleate myotubes. Myotubes organize together to form striated muscle fibers. Page reference: 354 b. Myoblast – myotome – myotube – muscle fiber

Wolpert et al, Principles of Development 6e Test bank Feedback: No, skeletal muscle cells are derived from the myotome portion of the somite. These somitic cells become myoblasts that differentiate by synthesizing muscle-specific proteins and modifying their shape. These structural changes allow them to fuse to form multinucleate myotubes. Myotubes organize together to form striated muscle fibers. Page reference: 354 c. Myotome – myoblast – muscle fiber - myotube Feedback: Yes, skeletal muscle cells are derived from the myotome portion of the somite. These somitic cells become myoblasts that differentiate by synthesizing muscle-specific proteins and modifying their shape. These structural changes allow them to fuse to form multinucleate myotubes. Myotubes organize together to form striated muscle fibers. Page reference: 354 d. Myotome – myotube – myoblast – muscle fiber Feedback: No, skeletal muscle cells are derived from the myotome portion of the somite. These somitic cells become myoblasts that differentiate by synthesizing muscle-specific proteins and modifying their shape. These structural changes allow them to fuse to form multinucleate myotubes. Myotubes organize together to form striated muscle fibers. Page reference: 354 Type: multiple choice question Title: Chapter 08 - Question 04 04) Which of the following is not true of the MyoD protein? a. It promotes downstream muscle-specific transcription factors Feedback: No, this is true. MyoD is a transcription factor of the basic helix-loop-helix family. It functions to turn on muscle-specific genes that lead to muscle differentiation. Along with MyoD’s ability to positively regulate its own expression through feedback, many of the muscle genes it turns on do the same for themselves. This ensures a consistent muscle-specific genetic program during the differentiation process. Page reference: 353 b. It promotes its own production in a positive-feedback loop Feedback: No, this is true. MyoD is a transcription factor of the basic helix-loop-helix family, and can positively regulate its own expression through feedback on the Myod gene. It also functions to turn on muscle-specific genes that lead to muscle differentiation; many of these genes also act in positive feedback loops. This ensures a consistent muscle-specific genetic program during the differentiation process. Page reference: 353 *c. Mouse knock-outs lacking MyoD function do not develop skeletal muscle Feedback: Yes, this is not true. Mice lacking MyoD function make normal skeletal muscle. This reflects a level of redundancy in the system whereby one protein can cover for the absence of another to provide a backup mechanism. Page reference: 353 d. It is only expressed in muscle precursors and muscle cells Feedback: No, this is true. MyoD protein is a master regulatory protein for initiating the cascade of events leading to muscle differentiation. MyoD is solely expressed in muscle precursors and muscle cells. Page reference: 353 Type: multiple choice question Title: Chapter 08 - Question 05 05) Which of the following surrounds a stem cell and maintains its proliferative state and selfrenewal capabilities? *a. Stem-cell niche Feedback: Yes, the ability of stem cells to self-renew and differentiate is regulated by the immediate environment. These surrounding cells and molecules are referred to as a “niche.” Page reference: 358

Wolpert et al, Principles of Development 6e Test bank b. Stem-cell milieu Feedback: No, the ability of stem cells to self-renew and differentiate is regulated by the immediate environment. These surrounding cells and molecules are referred to as a “niche.” Page reference: 358 c. Stem-cell marrow Feedback: No, the ability of stem cells to self-renew and differentiate is regulated by the immediate environment. These surrounding cells and molecules are referred to as a “niche.” Page reference: 358 d. Stem-cell complex Feedback: No, the ability of stem cells to self-renew and differentiate is regulated by the immediate environment. These surrounding cells and molecules are referred to as a “niche.” Page reference: 358 Type: multiple choice question Title: Chapter 08 - Question 06 06) Which of the options given is the DNA control region that regulates switching in the betafamily globin genes during development? a. Globin control region Feedback: No, the locus control region, or LCR,is a 10,000 base pair control element roughly 5000 bases upstream of the epsilon globin gene. It controls the switching of beta-family globin genes during development. Proteins bound to the LCR form a complex at the promoters of successive globin genes as the chromosome loops to support the formation of this complex. Page reference: 364 b. Locus enhancer region Feedback: No, the locus control region, or LCR, is a 10,000 base pair control element roughly 5,000 bases upstream of the sigma globin gene. It controls the switching of beta-family globin genes during development. The current model assumes proteins bound to the LCR form a complex at the promoters of successive globin genes as the chromosome loops to support the formation of this complex. Page reference: 364 c. Globin activation region Feedback: No, the locus control region, or LCR, is a 10,000 base pair control element roughly 5,000 bases upstream of the sigma globin gene. It controls the switching of beta-family globin genes during development. The current model assumes proteins bound to the LCR form a complex at the promoters of successive globin genes as the chromosome loops to support the formation of this complex. Page reference: 364 *d. Locus control region Feedback: Yes, the locus control region, or LCR, is a 10,000 base pair control element roughly 5000 bases upstream of the sigma globin gene. It controls the switching of the beta-family globin genes during development. The current model assumes proteins bound to the LCR form a complex at the promoters of successive globin genes as the chromosome loops to support the formation of this complex. Page reference: 364 Type: multiple choice question Title: Chapter 08 - Question 07 07) Epidermal skin stem cells reside within the basal layer of the epidermis, just above the basement membrane and the dermis. What is the stem-cell niche for these particular stem cells? *a. The basement membrane Feedback: Yes, the basement membrane, along with fibroblasts within the dermis, send signals to overlying stem cells in the basal layer to keep them proliferative. Cells that leave the basal layer, and move away from their niche, differentiate into keratinocytes of the outermost epidermal layer.

Wolpert et al, Principles of Development 6e Test bank Page reference: 356 b. Neighbouring epidermal cells Feedback: No, the basement membrane, along with fibroblasts within the dermis, send signals to overlying stem cells in the basal layer to keep them proliferative. Cells that leave the basal layer, and move away from their niche, differentiate into keratinocytes of the outermost epidermal layer. Page reference: 356 c. Sebaceous glands Feedback: No, the basement membrane, along with fibroblasts within the dermis, send signals to overlying stem cells in the basal layer to keep them proliferative. Cells that leave the basal layer, and move away from their niche, differentiate into keratinocytes of the outermost epidermal layer. Page reference: 356 d. Sweat glands Feedback: No, the basement membrane, along with fibroblasts within the dermis, send signals to overlying stem cells in the basal layer to keep them proliferative. Cells that leave the basal layer, and move away from their niche, differentiate into keratinocytes of the outermost epidermal layer. Page reference: 356 Type: multiple choice question Title: Chapter 08 - Question 08 08) The epithelial lining of the small intestine is exposed to a harsh environment and undergoes continuous cell loss. In which region of the small intestine do stem cells reside? a. The goblet Feedback: No, the crypt penetrates the underlying connective tissue and supports the replenishment of lost cells on a continuous basis. The crypt contains two types of stem cells. Page reference: 370 b. The villus Feedback: No, the crypt penetrates the underlying connective tissue and supports the replenishment of lost cells on a continuous basis. The crypt contains two types of stem cells. The villus is a finger-like projection into the lumen of the small intestine. Stem cells within the crypt contribute new cells to the epithelial lining of the villus. Page reference: 370 c. The mesenchyme Feedback: No, the crypt penetrates the underlying connective tissue and supports the replenishment of lost cells on a continuous basis. The crypt contains two types of stem cells. Page reference: 370 *d. The crypt Feedback: Yes, the crypt penetrates the underlying connective tissue and supports the replenishment of lost cells on a continuous basis. The crypt contains two types of stem cells. Page reference: 370 Type: multiple choice question Title: Chapter 08 - Question 09 09) From which group of cells are embryonic stem cells derived? a. Trophectoderm Feedback: No, embryonic stem cells are derived from the inner cell mass of a blastocyst. The primitive endoderm and trophectoderm give rise to extra-embryonic tissues in an intact embryo. Although both tissues can be converted into self-renewing stem cells in culture, they are “lineagespecific stem cells” and can only differentiate into their usual cell types. Page reference: 374 b. Primitive endoderm Feedback: No, embryonic stem cells are derived from the inner cell mass of a blastocyst. The primitive endoderm and trophectoderm give rise to extra-embryonic tissues in an intact embryo. Although both tissues can be converted into self-renewing stem cells in culture, they are “lineagespecific stem cells” and can only differentiate into their usual cell types.

Wolpert et al, Principles of Development 6e Test bank Page reference: 374 c. Extra-embryonic ectoderm Feedback: No, embryonic stem cells are derived from the inner cell mass of a blastocyst. The cells of the inner cell mass are fated to become every cell in the future embryo and adult—that is, they are pluripotent. Page reference: 374 *d. Inner cell mass Feedback: Yes, embryonic stem cells are derived from the inner cell mass of a blastocyst. The cells of the inner cell mass are fated to become every cell in the future embryo and adult—that is, they are pluripotent. Page reference: 374 Type: multiple choice question Title: Chapter 08 - Question 10 10) Which of the following is not true of somatic cell nuclear transfer? a. It is used to produce animal clones Feedback: No, this is true. The resulting embryo that is produced, following development of an egg that has undergone a transplant of an adult differentiated somatic cell nucleus, will be genetically identical to the nuclear donor and is therefore a clone. Page reference: 379 b. A nucleus from an adult differentiated cell is often used Feedback: No, this is true. A somatic cell is an adult body cell that is not of the germ-line. Following the removal of an egg’s nucleus, an adult differentiated cell’s nucleus is inserted into the egg. The resulting embryo that is produced will be genetically identical to the nuclear donor. Page reference: 379 c. It can be used to create patient-specific stem cells Feedback: No, this is true. The resulting embryo that is produced, following development of an egg that has undergone a transplant of an adult differentiated somatic cell nucleus, will be genetically identical to the nuclear donor. If a patient, in need of a specific type of cell, donates the nucleus, the inner cell mass from the developing blastocyst can be used to extract patientspecific stem cells. This is referred to as “therapeutic cloning.” Page reference: 379 *d. The resulting embryo is genetically identical to the egg donor Feedback: Yes, this is not true. The resulting embryo that is produced, following development of an egg that has undergone a transplant of an adult differentiated somatic cell nucleus, will be genetically identical to the nuclear donor. The egg has had its nucleus removed prior to the transplantation. Page reference: 379

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 9 - Question 01 01) Which of the options given is not true of Drosophila germ-line development? *a. Germ-line development begins in the anterior region of the egg Feedback: Yes, this is not true. The pole plasm, characterized by large organelles, and polar granules containing proteins and RNAs, resides within the posterior pole. Nuclei that are surrounded by the pole plasm are specified as germ-cell nuclei. Page reference: 401 b. Germ cells are derived from pole cells. Feedback: No, this is true. The pole plasm, characterized by large organelles, and polar granules containing proteins and RNAs, resides within the posterior pole. Nuclei that are surrounded by the pole plasm are specified as germ-cell nuclei. Page reference: 401 c. Shifting the position of pole plasm shifts the position of germ cell specification Feedback: No, this is true. The pole plasm, characterized by large organelles, and polar granules containing proteins and RNAs, resides within the posterior pole. Nuclei that are surrounded by the pole plasm are specified as germ-cell nuclei. Transplanting posterior pole plasm to the anterior region of the embryo causes anterior specification of pole cells. Page reference: 401 d. Germ cells are specified by inheriting cytoplasmic determinants Feedback: No, this is true. The pole plasm, characterized by large organelles, and polar granules containing proteins and RNAs, resides within the posterior pole. These proteins and RNAs are asymmetrically localized cytoplasmic determinants. Nuclei that are surrounded by the pole plasm are specified as germ-cell nuclei. Page reference: 401 Type: multiple choice question Title: Chapter 9 - Question 02 02) How many distinct germplasm regions are present in a zebrafish embryo? a. 1 Feedback: No, the zebrafish germplasm is distributed among four locations in the embryo. During cleavage, the germplasm segregates to specific daughter cells through asymmetric cell division. At the sphere stage, equal divisions begin producing roughly 30 primordial germ cells before migrating to the prospective gonads. Page reference: 405 b. 2 Feedback: No, the zebrafish germplasm is distributed among four locations in the embryo. During cleavage, the germplasm segregates to specific daughter cells through asymmetric cell division. At the sphere stage, equal divisions begin producing roughly 30 primordial germ cells before migrating to the prospective gonads. Page reference: 405 c. 3 Feedback: No, the zebrafish germplasm is distributed among four locations in the embryo. During cleavage, the germplasm segregates to specific daughter cells through asymmetric cell division. At the sphere stage, equal divisions begin producing roughly 30 primordial germ cells before migrating to the prospective gonads. Page reference: 405 *d. 4 Feedback: Yes, the zebrafish germplasm is distributed among four locations in the embryo. During cleavage, the germplasm segregates to specific daughter cells through asymmetric cell division. At the sphere stage, equal divisions begin producing roughly 30 primordial germ cells before migrating to the prospective gonads. Page reference: 405

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 9 - Question 03 03) Which of the options given represents the pathway of primordial germ-cell migration in the mouse embryo? a. Hindgut – dorsal mesentery – primitive streak – genital ridge Feedback: No, the earliest detectable primordial germ cells migrate to the region posterior to the primitive streak. They then enter the hindgut endoderm and migrate along and across the dorsal mesentery and into the genital ridges. Primordial germ cells will then differentiate into eggs and sperm within the gonads derived from the genital ridge. Page reference: 404-405 *b. Primitive streak – hindgut – dorsal mesentery – genital ridge Feedback: Yes, the earliest detectable primordial germ cells migrate to the region posterior to the primitive streak. They then enter the hindgut endoderm and migrate along and across the dorsal mesentery and into the genital ridges. Primordial germ cells will then differentiate into eggs and sperm within the gonads derived from the genital ridge. Page reference: 405–405 c. Dorsal mesentery – hindgut – primitive streak – genital ridge Feedback: No, the earliest detectable primordial germ cells migrate to the region posterior to the primitive streak. They then enter the hindgut endoderm and migrate along and across the dorsal mesentery and into the genital ridges. Primordial germ cells will then differentiate into eggs and sperm within the gonads derived from the genital ridge. Page reference: 404–405 d. Primitive streak – dorsal mesentery – hindgut – genital ridge Feedback: No, the earliest detectable primordial germ cells migrate to the region posterior to the primitive streak. They then enter the hindgut endoderm and migrate along and across the dorsal mesentery and into the genital ridges. Primordial germ cells will then differentiate into eggs and sperm within the gonads derived from the genital ridge. Page reference: 404–405 Type: multiple choice question Title: Chapter 9 - Question 04 04) Which of the options given is true of mammalian oogenesis? a. Meiosis gives rise to four daughter cells of equal size Feedback: No, this is not true. Meiotic cell division is unequal, giving rise give rise to one large cell that becomes the oocyte and three smaller structures called polar bodies. Page reference: 408 *b. Meiosis is complete only occurs after fertilization Feedback: Yes, this is true. Mammalian fertilization takes place while the ooctye is arrested at metaphase II of the second meiotic division. Fertilization will promote the completion of meiosis. Page reference: 408 c. Meiosis gives rise to four genetically identical daughter cells Feedback: No, this is not true. Unlike mitosis, meiosis promotes genetic variation in daughter cells through genetic recombination, and independent assortment of chromosomes. Page reference: 408 d. Meiosis is completed while the female is an embryo Feedback: No, this is not true. Meiosis begins while the female is an embryo but it arrests in prophase I of the first meiotic division. This is the stage at which homologous chromosomes pair up and recombine genetic material. Page reference: 408 Type: multiple choice question Title: Chapter 9 - Question 05

Wolpert et al, Principles of Development 6e Test bank 05) Which type of embryo is formed from the activation of an unfertilized egg? a. Androgenetic Feedback: No, androgenetic embryos are derived from eggs that have been engineered to contain two paternal chromosomes. Parthenogenetic embryos are derived from the activation of development from an unfertilized egg. Page reference: 411 b. Gynogenetic Feedback: No, gynogenetic embryos are derived from eggs that have been engineered to contain two maternal chromosomes. Parthenogenetic embryos are derived from the activation of development from an unfertilized egg. Page reference: 411 *c. Parthenogenetic Feedback: Yes, parthenogenetic embryos are derived from the activation of development from an unfertilized egg. Page reference: 411 d. Epigenetic Feedback: No, parthenogenetic embryos are derived from the activation of development from an unfertilized egg. Page reference: 411 Type: multiple choice question Title: Chapter 9 - Question 06 06) Which of the following refers to the silencing of germ-cell-specific genes during early development? a. Germ-cell suppression Feedback: No, genomic imprinting is the process whereby certain genes are turned off in the sperm or egg and remain silenced during early embryonic development. Page reference: 411 b. Sex-specific inhibition Feedback: No, genomic imprinting is the process whereby certain genes are turned off in the sperm or egg and remain silenced during early embryonic development. Page reference: 411 *c. Genomic imprinting Feedback: Yes, genomic imprinting is the process whereby certain genes are turned off in the sperm or egg and remain silenced during early embryonic development. Page reference: 411 d. Genetic printing Feedback: No, genomic imprinting is the process whereby certain genes are turned off in the sperm or egg and remain silenced during early embryonic development. Page reference: 411 Type: multiple choice question Title: Chapter 9 - Question 07 07) What is the name of the Golgi-derived vesicle located in the head of sperm that aids in its penetration of the egg? a. Cortical granule Feedback: No, cortical granules are golgi-derived vesicles containing a variety of materials that help prevent polyspermy. Contents include enzymes that cleave sperm-binding proteins and cause expansion of the space between the vitelline membrane and zona pellucida. The outer layer is then hardened to form a fertilization membrane. Page reference: 416 b. Zona pellucida Feedback: No, the zona pellucida is a layer of glycoproteins secreted by the ooctye to act as a physical barrier.

Wolpert et al, Principles of Development 6e Test bank Page reference: 416 *c. Acrosome Feedback: Yes, the acrosome is the specialized golgi-derived vesicle in the head of the sperm that fuses with the sperm membrane to release its enzymatic contents. Actin polymerization occurs that extends a finger-like projection towards the egg. This acrosomal reaction aids in penetration of the egg. Binding proteins on the surface of the extended acrosome are also present to bind to the surface of the egg. Page reference: 416 d. Cumulus Feedback: No, cumulus cells are egg-bound follicle cells that are shed with the egg during ovulation. Page reference: 416 Type: multiple choice question Title: Chapter 9 - Question 08 08) What is the name of the Golgi-derived vesicle located under the plasma membrane of an egg to block polyspermy? *a. Cortical granule Feedback: Yes, cortical granules are Golgi-derived vesicles containing a variety of materials that help prevent polyspermy. Contents include enzymes that cleave sperm-binding proteins and cause expansion of the space between the vitelline membrane and zona pellucida. The outer layer is then hardened to form a fertilization membrane. Page reference: 418 b. Zona pellucida Feedback: No, the zona pellucida is a layer of glycoproteins secreted by the ooctye to act as a physical barrier. Page reference: 418 c. Acrosome Feedback: No, the acrosome is the specialized Golgi-derived vesicle in the head of the sperm that fuses with the sperm membrane to release its enzymatic contents. Actin polymerization occurs that extends a finger-like projection towards the egg. This acrosomal reaction aids in penetration of the egg. Binding proteins on the surface of the extended acrosome are also present to bind to the surface of the egg. Page reference: 418 d. Cumulus Feedback: No, cumulus cells are egg-bound follicle cells that are shed with the egg during ovulation. Page reference: 418 Type: multiple choice question Title: Chapter 9 - Question 09 09) Which ion controls the slow block to polyspermy? a. Sodium Feedback: No, the slow block to polyspermy is controlled by a release of intracellular calcium. A wave of calcium promotes cortical granule fusion with the egg’s cytoplasm after fertilization. Page reference: 417 *b. Calcium Feedback: Yes, the slow block to polyspermy is controlled by a release of intracellular calcium. A wave of calcium promotes cortical granule fusion with the egg’s cytoplasm after fertilization. Page reference: 417 c. Potassium Feedback: No, the slow block to polyspermy is controlled by a release of intracellular calcium. A wave of calcium promotes cortical granule fusion with the egg’s cytoplasm after fertilization. Page reference: 417

Wolpert et al, Principles of Development 6e Test bank d. Chloride Feedback: No, the slow block to polyspermy is controlled by a release of intracellular calcium. A wave of calcium promotes cortical granule fusion with the egg’s cytoplasm after fertilization. Page reference: 417 Type: multiple choice question Title: Chapter 9 - Question 10 10) The presence of an SRY sequence in a mammalian genome causes the degradation of which of these structures? a. Wolffian duct Feedback: No, The SRY sequence results in differentiation of Sertoli cells. Sertoli cells are required for testis formation and sperm maturation. The synthesis of Müllerian-inhibiting substance, thus causing the degradation of the Müllerian duct. The Wollfian duct persists in males and will become the vas deferens. Page reference: 422 b. Vas deferens Feedback: No, The SRY sequence results in differentiation of Sertoli cells. Sertoli cells are required for testis formation and sperm maturation. The synthesis of Müllerian-inhibiting substance, thus causing the degradation of the Mullerian duct. The Wollfian duct persists in males and will become the vas deferens. Page reference: 422 c. Sertoli cells Feedback: No, The SRY sequence results in differentiation of Sertoli cells. Sertoli cells are required for testis formation and sperm maturation. The synthesis of Müllerian-inhibiting substance, thus causing the degradation of the Müllerian duct. The Wollfian duct persists in males and will become the vas deferens. Page reference: 422 *d. Müllerian duct Feedback: Yes, The SRY sequence results in differentiation of Sertoli cells. Sertoli cells are required for testis formation and sperm maturation. The synthesis of Müllerian-inhibiting substance, thus causing the degradation of the Müllerian duct. The Wollfian duct persists in males and will become the vas deferens. Page reference: 422

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 10 - Question 01 01) The apical ectodermal ridge runs in which direction in the developing limb bud? a. Antero-posterior Feedback: Yes, the apical ectodermal ridge is a thickening of the ectoderm at the distal tip of the limb bud. It runs in an antero-posterior direction along the boundary between dorsal and ventral ectoderm. Page reference: 447 *b. Dorso-ventral Feedback: No, the apical ectodermal ridge is a thickening of the ectoderm at the distal tip of the limb bud. It runs in an antero-posterior direction along the boundary between dorsal and ventral ectoderm. Page reference: 447 c. Proximo-distal Feedback: No, the apical ectodermal ridge is a thickening of the ectoderm at the distal tip of the limb bud. It runs in an antero-posterior direction along the boundary between dorsal and ventral ectoderm. Page reference: 447 d. Left–right Feedback: No, the apical ectodermal ridge is a thickening of the ectoderm at the distal tip of the limb bud. It runs in an antero-posterior direction along the boundary between dorsal and ventral ectoderm. Page reference: 447 Type: multiple choice question Title: Chapter 10 - Question 02 02) What is the correct flow of interactions that determines proper positioning and outgrowth of the forelimb? *a. Lateral plate – Hox – Tbx5 – FGF-10 – apical ectodermal ridge Feedback: Yes, the anterior-posterior positioning of the fore- and hindlimb is determined by the combinatorial action of Hox genes within the lateral plate mesoderm. Tbx transcription factors become expressed specifically in limb-forming regions, with Tbx5 in the prospective forelimb. Tbx factors control the local production of FGF-10, which in turn promotes the development of the apical ectodermal ridge (AER). The AER establishes a positive feedback loop that maintains consistent outgrowth of the limb from the side of the embryo. Page reference: 457 b. Lateral plate – Tbx4 – Hox – FGF-10 - apical ectodermal ridge Feedback: No, the anterior-posterior positioning of the fore- and hindlimb is determined by the combinatorial action of Hox genes within the lateral plate mesoderm. Tbx transcription factors become expressed specifically in limb-forming regions, with Tbx5 in the prospective forelimb. Tbx factors control the local production of FGF-10, which in turn promotes the development of the apical ectodermal ridge (AER). The AER establishes a positive feedback loop that maintains consistent outgrowth of the limb from the side of the embryo. Page reference: 457 c. Lateral plate – Hox – Tbx4 – FGF-10 - apical ectodermal ridgeFeedback: No, the anterior-posterior positioning of the fore- and hindlimb is determined by the combinatorial action of Hox genes within the lateral plate mesoderm. Tbx transcription factors become expressed specifically in limb-forming regions, with Tbx5 in the prospective forelimb. Tbx factors control the local production of FGF-10, which in turn promotes the development of the apical ectodermal ridge (AER). The AER establishes a positive feedback loop that maintains consistent outgrowth of the limb from the side of the embryo. Page reference: 457 d. Lateral plate – Tbx5 – Hox – FGF-10 - apical ectodermal ridge

Wolpert et al, Principles of Development 6e Test bank Feedback: No, the anterior-posterior positioning of the fore- and hindlimb is determined by the combinatorial action of Hox genes within the lateral plate mesoderm. Tbx transcription factors become expressed specifically in limb-forming regions, with Tbx5 in the prospective forelimb. Tbx factors control the local production of FGF-10, which in turn promotes the development of the apical ectodermal ridge (AER). The AER establishes a positive feedback loop that maintains consistent outgrowth of the limb from the side of the embryo. Page reference: 457 Type: multiple choice question Title: Chapter 10 - Question 03 03) Which of the following refers to a chemical or infection that interferes with embryonic development, leading to defects in the animal? *a. Teratogen Feedback: Yes, a teratogen is an external agent, such as a chemical or infection, that interferes with embryonic development, leading to defects in the embryo and the animal. Page reference: 472 b. Mutagen Feedback: No, a teratogen is an external agent, such as a chemical or infection, that interferes with embryonic development, leading to defects in the embryo and the animal. Some mutagens, those that cause mutations in a DNA sequence, can be teratogens but not all mutagens are teratogens. Page reference: 472 c. Morphogen Feedback: No, a teratogen is an external agent, such as a chemical or infection, that interferes with embryonic development, leading to defects in the embryo and the animal. Some morphogens, in large excess, can give rise to teratogenic effects. However, a teratogen is a strict term used for an external substance for its deleterious effects on the embryo. Page reference: 472 d. Carcinogen Feedback: No, a teratogen is an external agent, such as a chemical or infection, that interferes with embryonic development, leading to defects in the embryo and the animal. A carcinogen is an agent that causes cancer. Page reference: 472 Type: multiple choice question Title: Chapter 10 - Question 04 04) Which of the following intercellular signaling pathways directly controls the sequence of limb digits across the antero-posterior axis? a. FGF Feedback: No, Sonic hedgehog (Shh) is the polarizing morphogen within the developing limb. It is expressed within the posterior limb mesenchyme, within the zone of polarizing activity (ZPA). When the ZPA is transplanted to, or if Shh expression is forced in, the anterior limb mesenchyme, the limb develops mirror-image duplication of digits, bones, muscles, and tendons. Fibroblast growth factor controls the outgrowth of the limb from the side of the embryo. Page reference: 466 *b. Shh Feedback: Yes, Sonic hedgehog (Shh) is the polarizing morphogen within the developing limb. It is expressed within the posterior limb mesenchyme, within the zone of polarizing activity (ZPA). When the ZPA is transplanted to, or if Shh expression is forced in, the anterior limb mesenchyme, the limb develops mirror-image duplication of digits, bones, muscles, and tendons. Page reference: 466 c. Wnt Feedback: No, Sonic hedgehog (Shh) is the polarizing morphogen within the developing limb. It is expressed within the posterior limb mesenchyme, within the zone of polarizing activity (ZPA).

Wolpert et al, Principles of Development 6e Test bank When the ZPA is transplanted to, or if Shh expression is forced in, the anterior limb mesenchyme, the limb develops mirror-image duplication of digits, bones, muscles, and tendons. Although there are interactions between Wnt and Shh signals, Wnt signals directly control the dorso-ventral patterning of the limb. Page reference: 466 d. BMP Feedback: No, Sonic hedgehog (Shh) is the polarizing morphogen within the developing limb. It is expressed within the posterior limb mesenchyme, within the zone of polarizing activity (ZPA). When the ZPA is transplanted to, or if Shh expression is forced in, the anterior limb mesenchyme, the limb develops mirror-image duplication of digits, bones, muscles, and tendons. Page reference: 466 Type: multiple choice question Title: Chapter 10 - Question 05 05) Which of the following intercellular signaling pathways directly controls the direction of knee and knuckle bending? a. FGF Feedback: No, Wnt7a is expressed within the dorsal limb ectoderm. Mutations in the Wnt7a gene give rise to a double ventral limb whereby dorsal tissues adopt ventral fates. The Wnt7a protein diffuses into the dorsal mesoderm and induces the expression of the Lmx1b transcription factor in the dorsal compartment of the underlying mesenchyme. Human mutations in the LMX1B gene causes nail-patella syndrome, in which dorsal structures are malformed or absent. Page reference: 471 b. Shh Feedback: No, Wnt7a is expressed within the dorsal limb ectoderm. Mutations in the Wnt7a gene gives rise to a double ventral limb whereby dorsal tissues adopt ventral fates. The Wnt7a protein diffuses into the dorsal mesoderm and induces the expression of the Lmx1b transcription factor in the dorsal compartment of the underlying mesenchyme. Human mutations in the LMX1B gene causes nail-patella syndrome, in which dorsal structures are malformed or absent. Page reference: 471 *c. Wnt Feedback: Yes, Wnt7a is expressed within the dorsal limb ectoderm. Mutations in the Wnt7a gene gives rise to a double ventral limb whereby dorsal tissues adopt ventral fates. The Wnt7a protein diffuses into the dorsal mesoderm and induces the expression of the Lmx1b transcription factor in the dorsal compartment of the underlying mesenchyme. Human mutations in the LMX1B gene causes nail-patella syndrome, in which dorsal structures are malformed or absent. Page reference: 471 d. Notch Feedback: No, Wnt7a is expressed within the dorsal limb ectoderm. Mutations in the Wnt7a gene gives rise to a double ventral limb whereby dorsal tissues adopt ventral fates. The Wnt7a protein diffuses into the dorsal mesoderm and induces the expression of the Lmx1b transcription factor in the dorsal compartment of the underlying mesenchyme. Human mutations in the LMX1B gene causes nail-patella syndrome, in which dorsal structures are malformed or absent. Page reference: 471 Type: multiple choice question Title: Chapter 10 - Question 06 06) Which mechanism underlies the formation of separate digits? a. FGF induces apoptosis of interdigital cells Feedback: No, BMP signaling in interdigital cells forces them to undergo apoptosis. FGF signals as a survival signal for these cells and a balance between both pathways exists to establish a switch. In some animals this webbing remains while it is programmed to die in others. Since apoptosis is a normal part of development, particularly for the limb, necrosis is not an appropriate cell death process in limb development.

Wolpert et al, Principles of Development 6e Test bank Page reference: 481 b. Lack of FGF induces necrosis of interdigital cells Feedback: No, BMP signaling in interdigital cells forces them to undergo apoptosis. FGF signals as a survival signal for these cells and a balance between both pathways exists to establish a switch. In some animals this webbing remains while it is programmed to die in others. Since apoptosis is a normal part of development, particularly for the limb, necrosis is not an appropriate cell death process in limb development. Page reference: 481 *c. BMP induces apoptosis of interdigital cells Feedback: Yes, BMP signaling in interdigital cells forces them to undergo apoptosis. FGF signals as a survival signal for these cells and a balance between both pathways exists to establish a switch. In some animals this webbing remains while it is programmed to die in others. Since apoptosis is a normal part of development, particularly for the limb, necrosis is not an appropriate cell death process in limb development. Page reference: 481 d. Lack of BMP induces necrosis of interdigital cells Feedback: No, BMP signaling in interdigital cells forces them to undergo apoptosis. FGF signals as a survival signal for these cells and a balance between both pathways exists to establish a switch. In some animals this webbing remains while it is programmed to die in others. Since apoptosis is a normal part of development, particularly for the limb, necrosis is not an appropriate cell death process in limb development. Page reference: 481 Type: multiple choice question Title: Chapter 10 - Question 07 07) Which axis in the Drosophila wing is inherited through engrailed expression from the embryonic parasegment? *a. Antero-posterior Feedback: Yes, engrailed expression within the embryonic parasegment is inherited by the wing’s posterior compartment during imaginal disc formation. Engrailed turns on Hedgehog expression in posterior cells, which signals across the antero-posterior boundary to cells within the anterior compartment. Page reference: 443 b. Dorso-ventral Feedback: No, engrailed expression within the embryonic parasegment is inherited by the wing’s posterior compartment during imaginal disc formation. Engrailed turns on Hedgehog expression in posterior cells, which signals across the antero-posterior boundary to cells within the anterior compartment. Page reference: 443 c. Proximo-distal Feedback: No, engrailed expression within the embryonic parasegment is inherited by the wing’s posterior compartment during imaginal disc formation. Engrailed turns on Hedgehog expression in posterior cells, which signals across the antero-posterior boundary to cells within the anterior compartment. Page reference: 443 d. Left-right Feedback: No, engrailed expression within the embryonic parasegment is inherited by the wing’s posterior compartment during imaginal disc formation. Engrailed turns on Hedgehog expression in posterior cells, which signals across the antero-posterior boundary to cells within the anterior compartment. Page reference: 443 Type: multiple choice question Title: Chapter 10 - Question 08

Wolpert et al, Principles of Development 6e Test bank 08) Which of the following is synthesized along the antero-posterior wing boundary to act as a morphogen to cells in both compartments? *a. Decapentaplegic (Dpp) Feedback: Yes, dpp is synthesized, in response to hedgehog signaling, and secreted along the antero-posterior boundary and diffuses away to target cells on both sides of the boundary to form symmetric concentration gradients. Dpp controls the expression of downstream genes in a concentration-dependant manner. Three of these genes are spalt, optomotorblind, and brinker. These genes are transcription factors and do not act as diffusible morphogens. Page reference: 443 b. Spalt (Sal) Feedback: No, dpp is synthesized, in response to hedgehog signaling, and secreted along the antero-posterior boundary and diffuses away to target cells on both sides of the boundary to form symmetric concentration gradients. Dpp controls the expression of downstream genes in a concentration-dependant manner. Three of these genes are spalt, optomotorblind, and brinker. These genes are transcription factors and do not act as diffusible morphogens. Page reference: 443 c. Brinker (Brk) Feedback: No, dpp is synthesized, in response to hedgehog signaling, and secreted along the antero-posterior boundary and diffuses away to target cells on both sides of the boundary to form symmetric concentration gradients. Dpp controls the expression of downstream genes in a concentration-dependant manner. Three of these genes are spalt, optomotorblind, and brinker. These genes are transcription factors and do not act as diffusible morphogens. Page reference: 443 d. Optomotorblind (Omb) Feedback: No, dpp is synthesized, in response to hedgehog signaling, and secreted along the antero-posterior boundary and diffuses away to target cells on both sides of the boundary to form symmetric concentration gradients. Dpp controls the expression of downstream genes in a concentration-dependant manner. Three of these genes are spalt, optomotorblind, and brinker. These genes are transcription factors and do not act as diffusible morphogens. Page reference: 443 Type: multiple choice question Title: Chapter 10 - Question 09 09) Which of the following tissues signals to the overlying ectoderm in a vertebrate embryo to induce the lens placode? a. Surface ectoderm Feedback: No, the lens placode arises from the surface ectoderm. The posterior region of developing forebrain undergoes evagination, and bulges out. This evagination is called the optic vesicle, and extends out to interact with the overlying ectoderm. The interaction between the optic vesicle and the ectoderm induces the formation of a thickened ectoderm region that will become the lens, called a lens placode. Page reference: 495 b. Neural retina Feedback: No, the neural retina is induced by signals coming from the developing lens. The posterior region of developing forebrain undergoes evagination, and bulges out. This evagination is called the optic vesicle, and extends out to interact with the overlying ectoderm. The interaction between the optic vesicle and the ectoderm induces the formation of a thickened ectoderm region that will become the lens, called a lens placode. Page reference: 495 c. Cornea Feedback: No, the cornea arises from the ectoderm following invagination of the lens placode. The posterior region of developing forebrain undergoes evagination, and bulges out. This evagination is called the optic vesicle, and extends out to interact with the overlying ectoderm.

Wolpert et al, Principles of Development 6e Test bank The interaction between the optic vesicle and the ectoderm induces the formation of a thickened ectoderm region that will become the lens, called a lens placode. Page reference: 495 *d. Optic vesicle Feedback: Yes, the posterior region of developing forebrain undergoes evagination, and bulges out. This evagination is called the optic vesicle, and extends out to interact with the overlying ectoderm. The interaction between the optic vesicle and the ectoderm induces the formation of a thickened ectoderm region that will become the lens, called a lens placode. Page reference: 495 Type: multiple choice question Title: Chapter 10 - Question 10 10) Which of the following is not true of the pax6 gene? a. Loss of Pax6 function in humans leads to aniridia Feedback: No, this is true. People heterozygous for mutations in PAX6 have eye malformations known as aniridia. Aniridia is the partial or complete loss of the iris. Page reference: 498 b. Ectopic pax6 expression induces eye development in non-eye imaginal discs Feedback: No, this is true. Ectopic expression of mouse, Xenopus, ascidian, or squid pax6 genes in Drosophila imaginal discs induces the development of Drosophila eye structures in noneye imaginal discs. Page reference: 499 c. Pax6 function is evolutionarily conserved Feedback: No, this is true. The function of the pax6 gene is conserved as ectopic expression of mouse, Xenopus, ascidian, or squid pax6 genes in Drosophila imaginal discs induces the development of a Drosophila eye in non-eye imaginal discs. Loss of pax6 function leads to partial or complete loss of eyes in a wide variety of animals, including humans. Page reference: 498 *d. It encodes a intercellular signaling receptor Feedback: Yes, this is not true. The Pax6 protein is a transcription factor. It regulates an eyespecific genetic program that controls eye development. Page reference: 498

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 11 - Question 01 01) Which of the following functions as a local organizer to induce the development of the tectum and cerebellum in rostral and caudal postions, respectively? a. Zona limitans intrathalamica Feedback: No, the midbrain-hindbrain boundary (MHB) is the isthmus between the mid- and hindbrain segments of the developing brain. It secretes FGF-8 to pattern the tissues on both sides of the boundary. Transplantation studies unveiled its organizer-like function because of its effect on local development. Its presence in the posterior forebrain can transform presumptive thalamus into tectum while its presence in the anterior midbrain can transform presumptive medulla into cerebellum. Page reference: 510 *b. Midbrain–hindbrain boundary Feedback: Yes, the midbrain-hindbrain boundary (MHB) is the isthmus between the mid- and hindbrain segments of the developing brain. It secretes FGF-8 to pattern the tissues on both sides of the boundary. Transplantation studies unveiled its organizer-like function because of its effect on local development. Its presence in the posterior forebrain can transform presumptive thalamus into tectum while its presence in the anterior midbrain can transform presumptive medulla into cerebellum. Page reference: 510 c. Anterior neural ridge Feedback: No, the midbrain–hindbrain boundary (MHB) is the isthmus between the mid- and hindbrain segments of the developing brain. It secretes FGF-8 to pattern the tissues on both sides of the boundary. Transplantation studies unveiled its organizer-like function because of its effect on local development. Its presence in the posterior forebrain can transform presumptive thalamus into tectum while its presence in the anterior midbrain can transform presumptive medulla into cerebellum. Page reference: 510 d. Telencephalon Feedback: No, the midbrain–hindbrain boundary (MHB) is the isthmus between the mid- and hindbrain segments of the developing brain. It secretes FGF-8 to pattern the tissues on both sides of the boundary. Transplantation studies unveiled its organizer-like function because of its effect on local development. Its presence in the posterior forebrain can transform presumptive thalamus into tectum while its presence in the anterior midbrain can transform presumptive medulla into cerebellum. Page reference: 510 Type: multiple choice question Title: Chapter 11 - Question 02 02) Which term refers to the segments of hindbrain tissue separated by lineage-restriction boundaries? a. Rhondomeres Feedback: No, they are called rhombomeres. The hindbrain is also referred to as the rhombencephalon. Dye-labeled cells within one rhombomere do not cross over into adjacent rhombomeres, highlighting the presence of a boundary of lineage restriction. Page reference: 511 b. Rhabdomeres Feedback: No, rhabdomeres are ommatidial structures within the compound eyes of arthropods. The hindbrain is segmented as bulges of tissue, called rhombomeres. The hindbrain is also referred to as the rhombencephalon. Dye-labeled cells within one rhombomere do not cross over into adjacent rhombomeres, highlighting the presence of a boundary of lineage restriction. Page reference: 511 *c. Rhombomeres

Wolpert et al, Principles of Development 6e Test bank Feedback: Yes, the hindbrain is structured differently from the mid- and forebrains in that it is segmented as bulges of tissue, called rhombomeres. The hindbrain is also referred to as the rhombencephalon. Dye-labeled cells within one rhombomere do not cross over into adjacent rhombomeres, highlighting the presence of a boundary of lineage restriction. Page reference: 511 d. Telomeres Feedback: No, telomeres are the distal ends of chromosomes. The hindbrain is segmented as bulges of tissue, called rhombomeres. The hindbrain is also referred to as the rhombencephalon. Dye-labeled cells within one rhombomere do not cross over into adjacent rhombomeres, highlighting the presence of a boundary of lineage restriction. Page reference: 511 Type: multiple choice question Title: Chapter 11 - Question 03 03) On the basis of our knowledge of dorso-ventral patterning of the neural tube, how would you treat cultured embryonic stem cells in order to obtain motor neurons for regenerative medicine? *a. Sonic hedgehog + retinoic acid Feedback: Yes, Sonic hedgehog (Shh) and retinoic acid (RA) are inducers of motor neurons within the ventral region of the neural tube. Shh is secreted by the notochord before stimulating its own expression within cells of the floor plate. Diffusion of Shh away from the floor plate gives rise to specific types of motor neurons. Retinoic acid emanates from adjacent mesoderm to aid in this process. Together, Shh and retinoic acid are known to stimulate motor neuron differentiation in cultured embryonic stem cells. Page reference: 516 b. Sonic hedgehog + Bone morphogenetic protein Feedback: No, bone morphogenetic protein (BMP) is secreted by the overlying ectoderm before stimulating its own expression within cells of the roof plate. Diffusion of BMP away from the roof plate gives rise to specific types of commissural neurons. BMP counteracts the ventral effects of Shh and therefore would not work well to stimulate motor neuron development. Page reference: 516 c. Bone morphogenetic protein Feedback: No, bone morphogenetic protein (BMP) is secreted by the overlying ectoderm before stimulating its own expression within cells of the roof plate. Diffusion of BMP away from the roof plate gives rise to specific types of commissural neurons. BMP counteracts the ventral effects of Shh and therefore would not work well to stimulate motor neuron development. Page reference: 516 d. Bone morphogenetic protein + retinoic acid Feedback: No, bone morphogenetic protein (BMP) is secreted by the overlying ectoderm before stimulating its own expression within cells of the roof plate. Diffusion of BMP away from the roof plate gives rise to specific types of commissural neurons. Although Shh and retinoic acid induce motor neuron differentiation, BMP counteracts the ventral effects of Shh and therefore would not work well to stimulate motor neuron development. Page reference: 516 Type: multiple choice question Title: Chapter 11 - Question 04 04) Which of the following is not true of neuroblast formation in the Drosophila embryo? *a. Embryos that lack both Notch and Delta function do not develop neuroblasts Feedback: Yes, this is not true. Embryos that lack both Notch and Delta function make many more neuroblasts at the expense of the epidermis. Page reference: 522 b. Initially, all cells of the proneural cluster have the potential of becoming neuroblasts Feedback: No, this is true. Initially all cells within the proneural cluster have the potential of becoming neuroblasts. Delta-Notch signaling drives a lateral-inhibition process that limits this

Wolpert et al, Principles of Development 6e Test bank potential. Some cells express higher levels of Delta protein, allowing those cells to inhibit neural differentiation in adjacent cells by suppressing Delta and pro-neural gene expression in neighboring cells. Delta signals to adjacent cells through the Notch receptor. Page reference: 522 c. Cells in which the Notch receptor is activated become epidermal cells Feedback: No, this is true. Initially all cells within the proneural cluster have the potential of becoming neuroblasts. Delta-Notch signaling drives a lateral-inhibition process that limits this potential. Some cells express higher levels of Delta protein, allowing those cells to inhibit neural differentiation in adjacent cells by suppressing Delta and pro-neural gene expression in neighboring cells. Delta signals to adjacent cells through the Notch receptor. Page reference: 522 d. Cells that are Delta-expressing cells become neuroblasts Feedback: No, this is true. Initially all cells within the proneural cluster have the potential of becoming neuroblasts. Delta-Notch signaling drives a lateral-inhibition process that limits this potential. Some cells express higher levels of Delta protein, allowing those cells to inhibit neural differentiation in adjacent cells by suppressing Delta and pro-neural gene expression in neighboring cells. Delta signals to adjacent cells through the Notch receptor. Page reference: 522 Type: multiple choice question Title: Chapter 11 - Question 05 05) From which layer do all neurons and glia of the brain and spinal cord in a vertebrate embryo arise? a. Mantle zone Feedback: No, all the neurons and glia of the brain and spinal cord arise from the proliferative layer of the ventricular zone. Page reference: 526 b. Intermediate zone Feedback: No, all the neurons and glia of the brain and spinal cord arise from the proliferative layer of the ventricular zone. Page reference: 526 *c. Ventricular zone Feedback: Yes, all the neurons and glia of the brain and spinal cord arise from the proliferative layer of the ventricular zone. Page reference: 526 d. Marginal zone Feedback: No, all the neurons and glia of the brain and spinal cord arise from the proliferative layer of the ventricular zone. Page reference: 526 Type: multiple choice question Title: Chapter 11 - Question 06 06) As new neurons migrate outward to build up concentric layers of neural tissue in the brain and spinal cord, which layer consists of cell bodies and is referred to as gray matter? a. Ventricular zone Feedback: No, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The mantle zone layer consists of cell bodies and is referred to as gray matter. Page reference: 526 *b. Mantle zone Feedback: Yes, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The mantle zone layer consists of cell bodies and is referred to as gray matter. Page reference: 526

Wolpert et al, Principles of Development 6e Test bank c. Intermediate zone Feedback: No, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The mantle zone layer consists of cell bodies and is referred to as gray matter. Page reference: 526 d. Marginal zone Feedback: No, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The mantle zone layer consists of cell bodies and is referred to as gray matter. Page reference: 526 Type: multiple choice question Title: Chapter 11 - Question 07 07) As new neurons migrate outward to build up concentric layers of neural tissue in the brain and spinal cord, which layer consists of neuronal axons and is referred to as white matter? a. Ventricular zone Feedback: No, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The marginal zone layer consists of neuronal axons and is referred to as white matter. This arranges an inner core of gray matter (cell bodies) with an outer core of white matter (myelinated axons). Page reference: 526 b. Mantle zone Feedback: No, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The marginal zone layer consists of neuronal axons and is referred to as white matter. This arranges an inner core of gray matter (cell bodies) with an outer core of white matter (myelinated axons). Page reference: 526 c. Intermediate zone Feedback: No, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The marginal zone layer consists of neuronal axons and is referred to as white matter. This arranges an inner core of gray matter (cell bodies) with an outer core of white matter (myelinated axons). Page reference: 526 *d. Marginal zone Feedback: Yes, new neurons migrate outward from the ventricular zone to build up concentric layers of neural tissue. The marginal zone layer consists of neuronal axons and is referred to as white matter. This arranges an inner core of gray matter (cell bodies) with an outer core of white matter (myelinated axons). Page reference: 526 Type: multiple choice question Title: Chapter 11 - Question 08 08) Which of the following is not true of targeting motor neurons to specific regions of the developing limb? a. The transcription factor, Lim1, provides motor neurons with positional identity within the spinal cord Feedback: No, this is true. Lim1 has been shown to regulate the expression of EphA4 in lateral division neurons of the lateral motor column. The EphA4 is a receptor, allowing these neurons to sense the chemorepellent ligand, EphrinA, in ventral limb mesenchyme. This inhibits these particular axons from innervating the ventral limb and restricts their innervation to muscles in the dorsal region of the limb. Page reference: 536 b. Motor neurons are guided by chemorepellents

Wolpert et al, Principles of Development 6e Test bank Feedback: No, this is true. Lim1 has been shown to regulate the expression of EphA4 in lateral division neurons of the lateral motor column. The EphA4 is a receptor, allowing these neurons to sense the chemorepellent ligand, EphrinA, in ventral limb mesenchyme. This inhibits these particular axons from innervating the ventral limb and restricts their innervation to muscles in the dorsal region of the limb. Page reference: 536 c. Motor neurons express specific receptors that guide their migration into the limb Feedback: No, this is true. Lim1 has been shown to regulate the expression of EphA4 in lateral division neurons of the lateral motor column. The EphA4 is a receptor, allowing these neurons to sense the chemorepellent ligand, EphrinA, in ventral limb mesenchyme. This inhibits these particular axons from innervating the ventral limb and restricts their innervation to muscles in the dorsal region of the limb. Page reference: 536 *d. Inverting the neural tube results in failure of motor neurons to innervate their correct muscles Feedback: Yes, this is not true. Inverting small regions of the neural tube has been shown to cause motor neurons to take novel paths, but they complete the journey and target the correct muscles. This suggests that secreted factors in the limb help sort out migrating axons. Page reference: 535 Type: multiple choice question Title: Chapter 11 - Question 09 09) Which of the following is true of commissural axon guidance in the neural tube? *a. Changes in the Robo3 receptor are important for selectively preventing commissural neuron midline crossing Feedback: Yes, this is true. Commissural neurons are allowed to cross the midline once because Robo3 masks the Slit chemorepellent along the midline. If commissural neurons cross the midline, Robo3 no longer masks the chemorepellent and Robo1/2-positive neurons are prohibited from recrossing due to the presence of Slit protein at the midline. Page reference: 537 b. Netrin-1 binds to its receptor, DCC, and is a chemorepellant. Feedback: No, this is not true. Netrin-1, expressed in the floor plate, acts as a chemoattractant to neurons containing its receptor, DCC. Netrin-1 mutants lack commissural neuron migration to the floor plate. Page reference: 537 c. Robo1/2 is a receptor that attracts commissural neurons Feedback: No, this is not true. Robo1/2 is a receptor that binds to the extracellular Slit protein to act as a chemorepellent. Slit protein is present at the midline, thus preventing Robo1/2-positive commissural neurons from crossing the midline after doing so the first time. Page reference: 537 d. Commissural neurons are allowed to cross the midline multiple times Feedback: No, this is not true. Commissural neurons are allowed to cross the midline once because Robo3 masks the slit chemorepellent along the midline. If commissural neurons cross the midline, Robo3 no longer masks the chemorepellent and Robo1/2-positive neurons are prohibited from re-crossing due to the presence of Slit protein at the midline. Page reference: 537 Type: multiple choice question Title: Chapter 11 - Question 10 10) Which of the following is not associated with neuromuscular junctions? a. Acetylcholine receptors Feedback: No, this is associated with neuromuscular junctions as acetylcholine is the major neurotransmitter involved in neural-muscle communication. Receptors for acetylcholine are present on the post-synaptic muscle cell. Page reference: 543

Wolpert et al, Principles of Development 6e Test bank b. Synaptic cleft Feedback: No, this is associated with neuromuscular junctions. The axonal plasma membrane is separated from the muscle cell’s plasma membranes by a narrow space, called the synaptic cleft. Page reference: 543 c. Synaptic vesicle Feedback: No, this is associated with neuromuscular junctions. Synaptic vesicles containing neurotransmitter fuse with the neural plasma membrane and spill their contents into the synaptic cleft. Acetylcholine is the major neurotransmitter involved in nerve-muscle communication. Receptors for acetylcholine are present on the post-synaptic muscle cell. Page reference: 543 *d. Dopamine Feedback: Yes, this is not associated with neuromuscular junctions as acetylcholine is the major neurotransmitter involved in nerve-muscle communication. Receptors for acetylcholine are present on the post-synaptic muscle cell. Page reference: 543

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 12 - Question 01 01) Which of the following refers to the ability to replace missing body parts by the regrowth and repatterning of somatic tissue? a. Metamorphosis Feedback: No, metamorphosis is the radical change and the development of new organs as an organism transforms into adult form. Regeneration is the ability to replace missing body parts by the regrowth and repatterning of somatic tissue. Page reference: 556 *b. Regeneration Feedback: Yes, regeneration is the ability to replace missing body parts by the regrowth and repatterning of somatic tissue. Page reference: 556 c. Growth Feedback: No, growth is the increase in mass or size of a tissue or organism. Regeneration is the ability to replace missing body parts by the regrowth and repatterning of somatic tissue. Page reference: 556 d. Homeostasis Feedback: No, homeostasis is the physiological ability to maintain the body’s internal environment. Regeneration is the ability to replace missing body parts by the regrowth and repatterning of somatic tissue. Page reference: 556 Type: multiple choice question Title: Chapter 12 - Question 02 02) Growth is the increase in mass or overall size of a tissue or organism. Which of the following is not a contributor to growth? a. Proliferation Feedback: No, this is a contributor to growth. Cell proliferation increases the number of cells by mitotic cell division. Page reference: 557 b. Enlargement Feedback: No, this is a contributor to growth. Cell enlargement is the increase in cellular mass. Page reference: 557 c. Accretionary growth Feedback: No, this is a contributor to growth. Accretionary growth is the increase in volume of the extracellular space through secretion of large quantities of extracellular matrix by cells. Page reference: 557 *d. Apoptosis Feedback: Yes, this is not a contributor to growth. Indeed, apoptosis, or programmed cell death, is an active contributor to decreasing the number of cells in a developing animal. Two examples are the mammalian nervous system and the nematode body where a great number of cells is initially produced than is present in final form. Page reference: 557 Type: multiple choice question Title: Chapter 12 - Question 03 03) Which of the following is the transcriptional co-activator component to the Drosophila Hippo pathway? a. Hippo Feedback: No, Yorkie is the transcriptional co-activator of the Hippo pathway. It promotes the expression of genes that promote cell proliferation. Its translocation to the nucleus is dependent on its phosphorylation status. If it is phosphorylated by the Warts kinase, Yorkie will remain in the cytoplasm. Warts activity is modified by the Hippo kinase.

Wolpert et al, Principles of Development 6e Test bank Page reference: 561 b. Warts Feedback: No, Yorkie is the transcriptional co-activator of the Hippo pathway. It promotes the expression of genes that promote cell proliferation. Its translocation to the nucleus is dependent on its phosphorylation status. If it is phosphorylated by the Warts kinase, Yorkie will remain in the cytoplasm. Warts activity is modified by the Hippo kinase. Page reference: 561 c. Merlin Feedback: No, Yorkie is the transcriptional co-activator of the Hippo pathway. It promotes the expression of genes that promote cell proliferation. Its translocation to the nucleus is dependent on its phosphorylation status. If it is phosphorylated by the Warts kinase, Yorkie will remain in the cytoplasm. Warts activity is modified by the Hippo kinase. Page reference: 561 *d. Yorkie Feedback: Yes, Yorkie is the transcriptional co-activator of the Hippo pathway. It promotes the expression of genes that promote cell proliferation. Its translocation to the nucleus is dependent on its phosphorylation status. If it is phosphorylated by the Warts kinase, Yorkie will remain in the cytoplasm. Warts activity is modified by the Hippo kinase. Page reference: 561 Type: multiple choice question Title: Chapter 12 - Question 04 04) Adenomatous polyposis coli (APC), a Wnt pathway member, is a tumor suppressor protein. Which of the options given is true of the APC protein? a. Its normal function promotes mitotic cell division Feedback: No, this is not true. Tumor suppressor proteins suppress mitotic division. Page reference: 564 b. Its normal function suppresses apoptosis Feedback: No, this is not true. Tumor suppressor proteins promote apoptosis. Page reference: 564 c. Mutations in the APC gene are inherited in a dominant fashion Feedback: No, this is not true. Tumor suppressor mutations are recessive due to the presence of the wild-type functioning copy on the other homologous chromosome. Tumor progression is not often observed in heterozygotes for tumor suppressor mutations. Page reference: 564 *d. Loss of APC function promotes mitosis Feedback: Yes, this is true. Tumor suppressor proteins suppress mitotic division. Therefore, loss of the APC tumor suppressor protein would increase the level of mitotic divisions. Page reference: 564 Type: multiple choice question Title: Chapter 12 - Question 05 05) Which of the following represents the correct flow of post-natal growth control? a. Pituitary – IGF-1 – liver – growth hormone Feedback: No, this is not correct. The hypothalamus stimulates release of growth hormone by the pituitary through the action of growth hormone-releasing hormone. The liver responds to growth hormone by synthesizing and releasing insulin-like growth factors 1 and 2. Page reference: 568 b. Liver – IGF-1 – Pituitary – growth hormone Feedback: No, this is not correct. The hypothalamus stimulates release of growth hormone by the pituitary through the action of growth hormone-releasing hormone. The liver responds to growth hormone by synthesizing and releasing insulin-like growth factor 1 and 2. Page reference: 568 c. Liver – growth hormone – Pituitary – IGF-1

Wolpert et al, Principles of Development 6e Test bank Feedback: No, this is not correct. The hypothalamus stimulates release of growth hormone by the pituitary through the action of growth hormone-releasing hormone. The liver responds to growth hormone by synthesizing and releasing insulin-like growth factor 1 and 2. Page reference: 568 *d. Pituitary – growth hormone – liver – IGF-1 Feedback: Yes, this is correct. The hypothalamus stimulates release of growth hormone by the pituitary through the action of growth hormone-releasing hormone. The liver responds to growth hormone by synthesizing and releasing insulin-like growth factor 1 and 2. Page reference: 568 Type: multiple choice question Title: Chapter 12 - Question 06 06) Which of the following hormones induces molting in arthropods? a. Growth hormone Feedback: No, ecdysone induces molting in arthropods. Page reference: 574 b. Testosterone Feedback: No, ecdysone induces molting in arthropods. Page reference: 574 c. Juvenile hormone Feedback: No, juvenile hormone inhibits metamorphosis and maintains the arthropod larval state. Ecdysone induces molting in arthropods. Page reference: 574 *d. Ecdysone Feedback: Yes, ecdysone induces molting in arthropods. Page reference: 574 Type: multiple choice question Title: Chapter 12 - Question 07 07) Which of the following hormones causes metamorphosis in amphibians? a. Juvenile hormone Feedback: No, juvenile hormone inhibits metamorphosis and maintains the arthropod larval state. Thyroid hormones stimulate metamorphosis in amphibians. Page reference: 578 b. Prolactin Feedback: No, prolactin delays metamorphosis in amphibians. Thyroid hormones stimulate metamorphosis in amphibians. Page reference: 578 c. Ecdysone Feedback: No, ecdysone induces molting in arthropods. Thyroid hormones stimulate metamorphosis in amphibians. Page reference: 578 *d. Thyroid hormone Feedback: Yes, thyroid hormones stimulate metamorphosis in amphibians. Page reference: 578 Type: multiple choice question Title: Chapter 12 - Question 08 08) What is the name given to the proliferative mass of undifferentiated cells at the site of amputation that gives rise to a regenerated limb in amphibians? a. Neoblast Feedback: No, the blastema is the proliferative mass of undifferentiated cells under the apical cap that gives rise to the regenerated limb. Blastema cells differentiate into missing tissues. Neoblasts are a population of dividing cells in planarians.

Wolpert et al, Principles of Development 6e Test bank Page reference: 581 b. Stem cell Feedback: No, the blastema is the proliferative mass of undifferentiated cells under the apical cap that gives rise to the regenerated limb. Blastema cells differentiate into missing tissues. Stem cells are self-renewing cells that give rise to various differentiated cells. Page reference: 581 c. Blastula Feedback: No, the blastema is the proliferative mass of undifferentiated cells under the apical cap that gives rise to the regenerated limb. Blastema cells differentiate into missing tissues. The blastula is an early stage of amphibian development. Page reference: 581 *d. Blastema Feedback: Yes, the blastema is the proliferative mass of undifferentiated cells under the apical cap that gives rise to the regenerated limb. Blastema cells differentiate into missing tissues. Page reference: 581 Type: multiple choice question Title: Chapter 12 - Question 09 09) Amphibian limb regeneration depends on the presence of nerves. Which of the following conditions would not support limb regeneration? a. Amputated limb with no other manipulation Feedback: No, this would support regeneration. Newt limbs have a naturally capacity to regenerate after amputation. Page reference: 588 b. Limb that has had its nerves removed early before limb development Feedback: No, this would support regeneration. Denervation after limb development has occurred renders limb regeneration dependent on nerves. Removing the nerves early before the limb has developed does not render limb regeneration dependent on nerve presence. Page reference: 588 c. Denervated limb with treatment of anterior gradient protein Feedback: No, this would support regeneration. Treatment of denervated limbs with anterior gradient protein (AG) rescues the failure to regenerate in the absence of nerves. Page reference: 588 *d. Limb that has had its nerves removed late after limb development Feedback: Yes, this would not support regeneration. Denervation after limb development has occurred renders limb regeneration dependent on nerves. Removing the nerves early before the limb has developed does not render limb regeneration dependent on nerve presence. Page reference: 588 Type: multiple choice question Title: Chapter 12 - Question 10 10) Which of the following is the earliest cellular change in the injured zebrafish heart? a. Electrical coupling Feedback: No, within a few hours after amputation, the endocardium rapidly increases the expression of the retinoic acid-synthesizing enzyme, raldh2. This is following by epicardial activation within a few days, vascularization of the muscle, and then electrical coupling as the missing cardiomyocytes are replaced. Page reference: 597 b. Vascularization of cardiac muscle Feedback: No, within a few hours after amputation, the endocardium rapidly increases the expression of the retinoic acid-synthesizing enzyme, raldh2. This is following by epicardial activation within a few days, vascularization of the muscle, and then electrical coupling as the missing cardiomyocytes are replaced. Page reference: 597

Wolpert et al, Principles of Development 6e Test bank c. Epicardial activation Feedback: No, within a few hours after amputation, the endocardium rapidly increases the expression of the retinoic acid-synthesizing enzyme, raldh2. This is following by epicardial activation within a few days, vascularization of the muscle, and then electrical coupling as the missing cardiomyocytes are replaced. Page reference: 597 *d. Endocardial activation Feedback: Yes, within a few hours after amputation, the endocardium rapidly increases the expression of the retinoic acid-synthesizing enzyme, raldh2. This is following by epicardial activation within a few days, vascularization of the muscle, and then electrical coupling as the missing cardiomyocytes are replaced. Page reference: 597 Type: multiple choice question Title: Chapter 12 - Question 11 11) Which of the following refers to the age-related decline in function? a. Dauer Feedback: No, dauer is the quiescent larval state in which it neither eats nor grows until food becomes available. Senescence is the age-related decline in function. Page reference: 599 b. Silence Feedback: No, senescence is the age-related decline in function. Page reference: 599 c. Lifespan Feedback: No, senescence is the age-related decline in function. Page reference: 599 *d. Senescence Feedback: Yes, senescence is the age-related decline in function. Page reference: 599

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 13 - Question 01 01) Which of the following is not true of the first cell division of a plant embryo? a. It establishes the apical-basal axis of the plant Feedback: No, this is true. The first division event is at right angles to the long axis, and divides into apical and basal daughter cells. One daughter cell, the suspensor, attaches the embryo to maternal tissue for nutrition purposes. The other daughter cell, the proembryo, will give rise to the rest of the embryo. This orientation establishes the apical-basal axis of the plant. Page reference: 616 b. It gives rise to a suspensor Feedback: No, this is true. The first division event is at right angles to the long axis, and divides into apical and basal daughter cells. One daughter cell, the suspensor, attaches the embryo to maternal tissue for nutrition purposes. The other daughter cell, the proembryo, will give rise to the rest of the embryo. This orientation establishes the apical-basal axis of the plant. Page reference: 616 *c. It is parallel to the long axis Feedback: Yes, this is not true. The first division event is at right angles to the long axis, and divides into apical and basal daughter cells. One daughter cell, the suspensor, attaches the embryo to maternal tissue for nutrition purposes. The other daughter cell, the proembryo, will give rise to the rest of the embryo. This orientation establishes the apical-basal axis of the plant. Page reference: 616 d. It gives rise to a proembryo Feedback: No, this is true. The first division event is at right angles to the long axis, and divides into apical and basal daughter cells. One daughter cell, the suspensor, attaches the embryo to maternal tissue for nutrition purposes. The other daughter cell, the proembryo, will give rise to the rest of the embryo. This orientation establishes the apical-basal axis of the plant. Page reference: 616 Type: multiple choice question Title: Chapter 13 - Question 02 02) At which stage do cotyledons start to develop wing-like structures? *a. Heart stage Feedback: Yes, the cotyledons start to develop wing-like structures during heart stage, giving the embryo a heart-like appearance. Page reference: 616 b. Globular stage Feedback: No, the cotyledons start to develop wing-like structures during heart stage, giving the embryo a heart-like appearance. Page reference: 616 c. Octant stage Feedback: No, the cotyledons start to develop wing-like structures during heart stage, giving the embryo a heart-like appearance. Page reference: 616 d. Triangular stage Feedback: No, the cotyledons start to develop wing-like structures during heart stage, giving the embryo a heart-like appearance. Page reference: 616 Type: multiple choice question Title: Chapter 13 - Question 03 03) Which of the following is not true of auxin? *a. Auxin functions as a diffusible extracellular signaling factor Feedback: Yes, this is not true. Auxin is actively transported between cells through the activity of PIN proteins. For example, the auxin-efflux protein PIN7 is localized to the apical plasma

Wolpert et al, Principles of Development 6e Test bank membrane of the basal cell. PIN7 actively transports auxin out of the basal cell and into the apical cell where it specifies apical cell fate. As auxin shifts between cell types, the established auxin gradient determines cell fate and establishes the apical-basal axis in the early embryo. Page reference: 618 b. It establishes the apical-basal axis Feedback: No, this is true. Auxin is actively transported between cells through the activity of PIN proteins. For example, the auxin-efflux protein PIN7 is localized to the apical plasma membrane of the basal cell. PIN7 actively transports auxin out of the basal cell and into the apical cell where it specifies apical cell fate. As auxin shifts between cell types, the established auxin gradient determines cell fate and establishes the apical-basal axis in the early embryo. Page reference: 618 c. It is actively transported from the basal cell into the apical cell Feedback: No, this is true. Auxin is actively transported between cells through the activity of PIN proteins. For example, the auxin-efflux protein PIN7 is localized to the apical plasma membrane of the basal cell. PIN7 actively transports auxin out of the basal cell and into the apical cell where it specifies apical cell fate. As auxin shifts between cell types, the established auxin gradient determines cell fate and establishes the apical-basal axis in the early embryo. Page reference: 618 d. The concentration gradient of auxin is necessary for specifying different cell fates Feedback: No, this is true. Auxin is actively transported between cells through the activity of PIN proteins. For example, the auxin-efflux protein PIN7 is localized to the apical plasma membrane of the basal cell. PIN7 actively transports auxin out of the basal cell and into the apical cell where it specifies apical cell fate. As auxin shifts between cell types, the established auxin gradient determines cell fate and establishes the apical-basal axis in the early embryo. Page reference: 618 Type: multiple choice question Title: Chapter 13 - Question 04 04) Which of the following is not a correct interpretation of a differentiated somatic cell’s ability to regenerate a new plant? a. Maternal determinants are of little or no importance for plant embryogenesis Feedback: No, this is a correct interpretation. It is unlikely that adult somatic cells would still continue to carry maternal determinants. Therefore, establishment of a new embryo from an adult cell bypasses a maternal contribution. Page reference: 620 b. The fate of many cells in the adult plant body is not fully determined Feedback: No, this is a correct interpretation. The ability of an adult plant cell to support the regeneration of a new embryo suggests that many cells remain totipotent. Page reference: 620 c. This opens up avenues for creating transgenic plants Feedback: No, this is a correct interpretation. The potential of a protoplast, made from an adult plant cell, to give rise to a new embryo following culture suggest that introduction of a transgene during culture is possible. Cultured cells are infected with Agrobacterium tumefaciens containing a recombinant plasmid with the trans-gene. Page reference: 620 *d. Many adult plant cells have lost their potential Feedback: yes, this is not a correct interpretation. The ability of an adult plant cell to support the regeneration of a new embryo suggests that many cells remain totipotent. Page reference: 620 Type: multiple choice question Title: Chapter 13 - Question 05 05) Which of the following is the type of meristem of the axillary bud near the base of a leaf? a. Shoot apical meristem

Wolpert et al, Principles of Development 6e Test bank Feedback: No, the axillary bud resides at the base of a leaf offshoot. The bud itself contains a meristem, known as the lateral shoot meristem. Page reference: 624 *b. Lateral shoot meristem Feedback: Yes, the axillary bud resides at the base of a leaf offshoot. The bud itself contains a meristem, known as the lateral shoot meristem. Page reference: 624 c. Inflorescence meristem Feedback: No, the axillary bud resides at the base of a leaf offshoot. The bud itself contains a meristem, known as the lateral shoot meristem. Page reference: 624 d. Floral meristem Feedback: yes, the axillary bud resides at the base of a leaf offshoot. The bud itself contains a meristem, known as the lateral shoot meristem. Page reference: 624 Type: multiple choice question Title: Chapter 13 - Question 06 06) A diffusible inhibitor emanating from the shoot apex inhibits the development of lateral buds below the apical bud. What is this inhibitory effect called? a. Lateral inhibition Feedback: No, the suppression of lateral buds immediately below the apical bud is referred to as apical dominance. Experiments using an agar block, infused with substances from an excised apex, suggested the involvement of a diffusible inhibitory molecule. Auxin satisfies as a candidate inhibitor, as application of auxin to a cut tip suppresses the usual overgrowth of lateral buds. Page reference: 624 *b. Apical dominance Feedback: Yes, the suppression of lateral buds immediately below the apical bud is referred to as apical dominance. Experiments using an agar block, infused with substances from an excised apex, suggested the involvement of a diffusible inhibitory molecule. Auxin satisfies as a candidate inhibitor, as application of auxin to a cut tip suppresses the usual overgrowth of lateral buds. Page reference: 624 c. Lateral dominance Feedback: No, the suppression of lateral buds immediately below the apical bud is referred to as apical dominance. Experiments using an agar block, infused with substances from an excised apex, suggested the involvement of a diffusible inhibitory molecule. Auxin satisfies as a candidate inhibitor, as application of auxin to a cut tip suppresses the usual overgrowth of lateral buds. Page reference: 624 d. Apex inhibition Feedback: yes, the suppression of lateral buds immediately below the apical bud is referred to as apical dominance. Experiments using an agar block, infused with substances from an excised apex, suggested the involvement of a diffusible inhibitory molecule. Auxin satisfies as a candidate inhibitor, as application of auxin to a cut tip suppresses the usual overgrowth of lateral buds. Page reference: 624 Type: multiple choice question Title: Chapter 13 - Question 07 07) What is the name of the slowly dividing, self-renewing stem cells of the central zone within a meristem? a. Centrals

Wolpert et al, Principles of Development 6e Test bank Feedback: No, the central zone of a meristem contains a group of slowly dividing, self-renewing stem cells called initials. They divide to give one daughter that remains a stem cell and one that continues to divide, leaves the meristem, and differentiates. Page reference: 625 b. Peripherals Feedback: No, the central zone of a meristem contains a group of slowly dividing, self-renewing stem cells called initials. They divide to give one daughter that remains a stem cell and one that continues to divide, leaves the meristem, and differentiates. Page reference: 625 *c. Initials Feedback: Yes, the central zone of a meristem contains a group of slowly dividing, self-renewing stem cells called initials. They divide to give one daughter that remains a stem cell and one that continues to divide, leaves the meristem, and differentiates. Page reference: 625 d. Apicals Feedback: No, the central zone of a meristem contains a group of slowly dividing, self-renewing stem cells called initials. They divide to give one daughter that remains a stem cell and one that continues to divide, leaves the meristem, and differentiates. Page reference: 625 Type: multiple choice question Title: Chapter 13 - Question 08 08) Which of the following axis is represented by the line between the leaf base to the leaf tip? *a. Proximo-distal Feedback: Yes, plants have a proximo-distal axis that is represented by the line between the leaf base and leaf tip. Page reference: 630 b. Adaxial-abaxial Feedback: No, plants have a proximo-distal axis that is represented by the line between the leaf base and leaf tip. The adaxial-abaxial axis, or dorso-ventral axis, is represented by the upper surface to the lower surface. Page reference: 630 c. Apical-basal Feedback: No, plants have a proximo-distal axis that is represented by the line between the leaf base and leaf tip. Page reference: 630 d. Dorso-ventral Feedback: No, plants have a proximo-distal axis that is represented by the line between the leaf base and leaf tip. The adaxial-abaxial axis, or dorso-ventral axis, is represented by the upper surface to the lower surface. Page reference: 630 Type: multiple choice question Title: Chapter 13 - Question 09 09) Which of the following is not true of homeotic floral mutations in Arabidopsis? a. One class of mutants affect whorls 1 and 2 Feedback: No, this is true. Homeotic floral mutations in Arabidopsis fall into three classes, each of which affects the organs of two adjacent whorls. The first class of mutants affects whorls 1 and 2. Page reference: 639 b. One class of mutants affect whorls 3 and 4 Feedback: No, this is true. Homeotic floral mutations in Arabidopsis fall into three classes, each of which affects the organs of two adjacent whorls. The third class of mutants affects whorls 3 and 4.

Wolpert et al, Principles of Development 6e Test bank Page reference: 639 c. One class of mutants affect whorls 2 and 3 Feedback: No, this is true. Homeotic floral mutations in Arabidopsis fall into three classes, each of which affects the organs of two adjacent whorls. The second class of mutants affects whorls 2 and 3. Page reference: 639 *d. One class of mutants affect whorls 1 and 4 Feedback: Yes, this is not true. Homeotic floral mutations in Arabidopsis fall into three classes, each of which affects the organs of two adjacent whorls. The first class of mutants affects whorls 1 and 2. The second class of mutants affects whorls 2 and 3. The third class of mutants affects whorls 3 and 4. Whorls 1 and 4 are not adjacent to each other. Page reference: 639

Type: multiple choice question Title: Chapter 13 - Question 10 10) What kinds of proteins do floral organ identity genes encode? a. Intercellular signaling ligands Feedback: No, all floral organ identity genes, also known as homeotic genes, encode transcription factors that are expressed in three concentric overlapping regions. These partition the meristem into four non-overlapping regions corresponding to the four whorls. Each whorl is given a unique identity by its particular homeotic gene combination. This is how organ identity is specified within the meristem. Page reference: 640 b. Cell-adhesion proteins Feedback: No, all floral organ identity genes, also known as homeotic genes, encode transcription factors that are expressed in three concentric overlapping regions. These partition the meristem into four non-overlapping regions corresponding to the four whorls. Each whorl is given a unique identity by its particular homeotic gene combination. This is how organ identity is specified within the meristem. Page reference: 640 c. Cell-surface receptors Feedback: No, all floral organ identity genes, also known as homeotic genes, encode transcription factors that are expressed in three concentric overlapping regions. These partition the meristem into four non-overlapping regions corresponding to the four whorls. Each whorl is given a unique identity by its particular homeotic gene combination. This is how organ identity is specified within the meristem. Page reference: 640 *d. Transcription factors Feedback: Yes, all floral organ identity genes, also known as homeotic genes, encode transcription factors that are expressed in three concentric overlapping regions. These partition the meristem into four non-overlapping regions corresponding to the four whorls. Each whorl is given a unique identity by its particular homeotic gene combination. This is how organ identity is specified within the meristem. Page reference: 640

Wolpert et al, Principles of Development 6e Test bank Type: multiple choice question Title: Chapter 14 - Question 01 01) Which of the following biologists was quoted as saying “nothing in biology makes sense unless viewed in the light of evolution?” *a. Theodosius Dobzhansky Feedback: Yes, Theodosius Dobzhansky was quoted as saying “nothing in biology makes sense unless viewed in the light of evolution.” Page reference: 653 b. Gregor Mendel Feedback: No, Theodosius Dobzhansky was quoted as saying “nothing in biology makes sense unless viewed in the light of evolution.” Page reference: 653 c. Charles Darwin Feedback: No, Theodosius Dobzhansky was quoted as saying “nothing in biology makes sense unless viewed in the light of evolution.” Page reference: 653 d. Hans Spemann Feedback: No, Theodosius Dobzhansky was quoted as saying “nothing in biology makes sense unless viewed in the light of evolution.” Page reference: 653 Type: multiple choice question Title: Chapter 14 - Question 02 02) The living unicellular group most closely related to multicellular animals is a. Filastereans Feedback: No, the nearest living group of animals related to animals is the choanoflagellates. Page reference: 658 *b. Choanoflagellates Feedback: Yes, the nearest living group of animals related to animals is the choanoflagellates. Page reference: 658 c. Ichthyosporeans Feedback: No, the nearest living group of animals related to animals is the choanoflagellates. Page reference: 658 d. Fungi Feedback: No, the nearest living group of animals related to animals is the choanoflagellates. Page reference: 658 Type: multiple choice question Title: Chapter 14 - Question 03 03) Trichoplax is a very simple two-layered organism harboring only four different cell types. In which phylum is Trichoplax classified? a. Porifera Feedback: No, the Porifera are the sponges. The Placozoa contains a single species of unique animal called Trichoplax. Page reference: 660 *b. Placozoa Feedback: Yes, Placozoa contains a single species of unique animal called Trichoplax. Page reference: 660 c. Ctenophora Feedback: No, the Ctenophora are the comb-jellies. The Placozoa contains a single species of unique animal called Trichoplax. Page reference: 660 d. Cnidaria

Wolpert et al, Principles of Development 6e Test bank Feedback: No, the Cnidaria are the jellyfish and relatives. The Placozoa contains a single species of unique animal called Trichoplax. Page reference: 660 Type: multiple choice question Title: Chapter 14 - Question 04 04) Vertebrates, mollusks, and nematodes are tripoblasts. Which embryonic characteristic classifies them as tripoblasts? *a. They have three germ layers Feedback: Yes, tripoblasts have three germ layers - endoderm, mesoderm, and ectoderm. Diploblasts have two germ layers – endoderm and ectoderm. Page reference: 660 b. Their digestive systems have three branches Feedback: No, tripoblasts have three germ layers - endoderm, mesoderm, and ectoderm. Diploblasts have two germ layers – endoderm and ectoderm. Page reference: 660 c. Their mid-blastula transition occurs at the third cleavage event Feedback: No, tripoblasts have three germ layers - endoderm, mesoderm, and ectoderm. Diploblasts have two germ layers – endoderm and ectoderm. Page reference: 660 d. Their tissues develop across three primary axes Feedback: No, tripoblasts have three germ layers - endoderm, mesoderm, and ectoderm. Diploblasts have two germ layers – endoderm and ectoderm. Page reference: 660 Type: multiple choice question Title: Chapter 14 - Question 05 05) What is ontogeny? a. The evolutionary history of a species or group Feedback: No, phylogeny is the evolutionary history of a species or group. Ontogeny is the development of an organism. Page reference: 655 b. The speed of developmental events Feedback: No, ontogeny is the development of an organism. Page reference: 655 *c. The development of an organism Feedback: Yes, ontogeny refers to the development of an organism. Page reference: 655 d. The sharing of embryological structures between animals Feedback: No, ontogeny is the development of an organism. Page reference: 655 Type: multiple choice question Title: Chapter 14 - Question 06 06) During Darwin’s visit to the Galapagos Islands he observed the differences in the shapes of beaks on finches and attributed those differences to the associated diets. We now know that calmodulin and a signaling pathway dictate these differences in size and shape. What is that signaling pathway? *a. BMP Feedback: Yes, BMP levels and location correlated with the length and shape of the beak. Injection of BMP into chick beaks can modify the chick beak length and shape. Page reference: 656 b. Wnt

Wolpert et al, Principles of Development 6e Test bank Feedback: No, BMP levels and location correlated with the length and shape of the beak. Injection of BMP into chick beaks can modify the chick beak length and shape. Page reference: 656 c. Shh Feedback: No, BMP levels and location correlated with the length and shape of the beak. Injection of BMP into chick beaks can modify the chick beak length and shape. Page reference: 656 d. Notch Feedback: No, BMP levels and location correlated with the length and shape of the beak. Injection of BMP into chick beaks can modify the chick beak length and shape. Page reference: 656 Type: multiple choice question Title: Chapter 14 - Question 07 07) While Drosophila have the simplest single set of Hox genes on a single chromosome, higher vertebrates typically have four sets across four different chromosomes. How many wholesale duplications of the Hox complex must have occurred during vertebrate evolution? *a. 2 Feedback: Yes, two duplications are believed to have occurred. Duplicating a single complex on one chromosome would give rise to two separate complexes. Duplication of each of these would give rise two a total of four Hox complexes. Page reference: 668 b. 1 Feedback: No, two duplications are believed to have occurred. Duplicating a single complex on one chromosome would give rise to two separate complexes. Duplication of each of these would give rise two a total of four Hox complexes. Page reference: 668 c. 3 Feedback: No, two duplications are believed to have occurred. Duplicating a single complex on one chromosome would give rise to two separate complexes. Duplication of each of these would give rise two a total of four Hox complexes. Page reference: 668 d. 4 Feedback: No, two duplications are believed to have occurred. Duplicating a single complex on one chromosome would give rise to two separate complexes. Duplication of each of these would give rise two a total of four Hox complexes. Page reference: 668 Type: multiple choice question Title: Chapter 14 - Question 08 08) What is the Drosophila chordin-related gene? *a. Short gastrulation Feedback: Yes, short gastrulation (sog) is the Drosophila chordin-related gene. It has a similar role in inhibiting the BMP4-related protein, Decapentaplegic (Dpp). Page reference: 674–675 b. BMP4 Feedback: No, short gastrulation (sog) is the Drosophila chordin-related gene. It has a similar role in inhibiting the BMP4-related protein, Decapentaplegic (Dpp). Page reference: 674–675 c. Chordino Feedback: No, short gastrulation (sog) is the Drosophila chordin-related gene. It has a similar role in inhibiting the BMP4-related protein, Decapentaplegic (Dpp). Chordino is the zebrafish chordin-related gene. Page reference: 674–675

Wolpert et al, Principles of Development 6e Test bank d. Long gastrulation Feedback: No, short gastrulation (sog) is the Drosophila chordin-related gene. It has a similar role in inhibiting the BMP4-related protein, Decapentaplegic (Dpp). Page reference: 674–675 Type: multiple choice question Title: Chapter 14 - Question 09 09) Humans have five digits on each hand and foot. All modern vertebrate species have no more than which number of digits? *a. 5 Feedback: Yes, all modern vertebrate species have no more than five digits. Page reference: 680 b. 6 Feedback: No, all modern vertebrate species have no more than five digits. Page reference: 680 c. 7 Feedback: No, all modern vertebrate species have no more than five digits. Page reference: 680 d. 8 Feedback: No, all modern vertebrate species have no more than five digits. Page reference: 680 Type: multiple choice question Title: Chapter 14 - Question 10 10) Which of the following refers to differences in the timing of developmental events? *a. Heterochrony Feedback: Yes, heterochrony refers to the differences in timing of developmental processes. Page reference: 692 b. Neoteny Feedback: No, heterochrony refers to the differences in timing of developmental processes. Page reference: 692 c. Ontogeny Feedback: No, heterochrony refers to the differences in timing of developmental processes. Page reference: 692 d. Synchrony Feedback: No, heterochrony refers to the differences in timing of developmental processes. Page reference: 692