Summary

This course involved the study of the molecular structures associated with living things. It combined the related subjects of biophysics, biochemistry, and genetics in order to give a clearer picture of the molecules that interact on a cellular level. The major macromolecules studied in the course included proteins, which make up structural molecules and enzymes, as well as nucleic acids, the underlying biochemical structures seen in ribonucleic acid (or RNA) and deoxyribonucleic acid (or DNA). The course also looked into the molecules used in the making of biomembranes, such as those that comprise the outer cell membrane and organelles. The molecular basis of the functions of prokaryotic and eukaryotic cells, including animal and plant cells, was also covered in this course.

Chapter one in the course introduced molecular biology by talking about the basics of biochemistry as it applies to life and living things. All of human life is based on water, which is a polar molecule that acts as a solvent for many biological molecules in living things. The bonds that make up biochemical molecules are also important in the discussion of molecular biology. The types of molecules that make up living organisms were also covered as were the different biochemical reactions that take place inside and outside the cell.

In chapter two of the course, the discussion moved from biochemistry to the biology of cells and cell structures. There are two major types of cells: prokaryotic cells and eukaryotic cells. These are quite different from one another in structure and function, which were covered in the chapter. Cells inside multicellular organisms must communicate with one another through different mechanisms. Animals that are complex and multicellular (such as are seen in the human body) have different cell types that form tissues. The tissues together form organ systems. The different types of tissues were covered in this chapter.

The focus of chapter three was the integration of cells into tissues. This chapter looked specifically into intercellular connections and how some of these connections create cell-

to-cell communication. In epithelial cell tissues, there is the basal lamina, the structure and function of which was covered in the chapter. In addition, the structure and function of connective tissue structures were discussed as were the adhesions seen in plant cells.

Chapter four in the course talked about the synthesis and structure of biomembranes. It covered fatty acid synthesis, which is how the basic molecules of biomembranes get created and incorporated into things like cell membranes and the membranes seen in organelles. The composition of membranes was also introduced, including the phospholipids and membrane proteins that together make up the cell membrane structure.

The main focus of chapter five was the different things that happen in transmembrane support. Water, for example, can pass through the membrane by osmosis—from a high concentration of water to a low concentration of water. Other types of membrane transport include simple and facilitated diffusion, as well as active transport. The sodium-potassium ATPase pump is particularly important in cell membrane transport. Symporters and antiporters also aid in the transport of certain molecules across the membrane. Ion transport helps account for a difference in electric potential between the inside and outside of the cell.

Chapter six in the course mainly covered proteins and their biochemistry. Proteins have several different characteristics, based on how they are made and on post-translational modification of the protein structures. The different factors that play a role into making proteins from amino acids was introduced in this chapter. Some proteins are functional enzymes; how these behave was covered in the chapter as were the different methods of detecting and characterizing proteins in molecular biology.

The structure and molecular processes of DNA and RNA were the topics of chapter seven. DNA and RNA have similar structures, although DNA is usually double-stranded and RNA is usually single-stranded. There are different types of RNA that vary according to their function. The chapter also talked about DNA replication, DNA repair, and the process of recombination.

There is a difference between prokaryotic genes and eukaryotic genes, which was part of the discussion of chapter eight in the course. Genetic material is divided up into genes, which are the readable segments of DNA in the organism. Transposons or transposable DNA were also covered, which is DNA that does not stay in the same place throughout the lifespan of the cell. Also included was a discussion of genomics, which is the collection of all the genes that exist as part of a given organism’s genetic material.

Cellular energetics was the subject of chapter nine in the course. There are hundreds of enzymes and reactions that take place as a result of cellular metabolism. Amino acids, fatty acids, and carbohydrates all get metabolized by the cell to varying degrees, usually with a common final pathway. Prokaryotic cells and eukaryotic cells have both similarities and differences in the way nutrients are metabolized. In addition, photosynthesis was covered as a metabolic process that plants and other photosynthetic organisms participate in.

The focus of chapter ten was the function of vesicles in exocytosis and endocytosis. Vesicular budding and fusion is a process where by small vesicles break off or fuse with the cell membrane or other membranes in order to dump or take up contents within the vesicles. This process can happen either to rid the cell of substances or take on substances by the cell. The process of receptor-mediated endocytosis was covered as part of this chapter as was the complex process of neurotransmitter secretion by nerve cells, which also involves vesicles.

Chapter eleven in the course introduced the topic of signal transduction or cell signaling. There are several signaling pathways that involve the ways that cells send and receive signals from other cells in multicellular organisms. There are ligands and receptors involved in signal transduction, of which there are many types. The largest family of membrane receptors is the G-coupled protein receptor family, which involves a specific protein type that many cells make use of in cell signaling. The ways this receptor operates in the cell membrane and within the cell were covered as part of this chapter.

Chapter twelve placed a focus on cell organization and on how aspects of cell organization control movement within the cell. There are many different types of

molecules involved in cellular organization, many of which contribute to the cell cytoskeleton. Organelles and substances move along the cytoskeleton so that the cell can have order and proper placement of intracellular structures. Some of these same fibrous proteins play a role in the cilia and flagella of different types of cells. In addition, cells migrate both as part of cell division and outside of cell division by virtue of the activity of the cell cytoskeleton.

Chapter thirteen in the course was about the eukaryotic cell cycle. There is a natural progression to the lifespan of a cell. It goes through growing phases, dividing phases, and the phases of death or apoptosis. There are specific controls over the eukaryotic cell cycle. The different phases of mitosis and meiosis were discussed along with the process of cell death, which is also called apoptosis.