Quiz

QUIZ

1. What kind of replication occurs in the replication of DNA?

a. Conservative b. Semi-conservative c. Dispersive d. A combination of semi-conservative and dispersive

Answer: b. Research has proven that DNA replication is semiconservative, which involves splitting of the DNA strand and the formation of a new strand half on the opposite side of both parent strands.

2. What enzyme is most responsible for DNA replication?

a. DNA polymerase b. Helicase c. DNA gyrase d. Topoisomerase

Answer: a. The main enzyme that is responsible for DNA replication is DNA polymerase, which is responsible for creating the daughter strand on the DNA molecule.

3. What is not a difference between eukaryotic DNA replication and prokaryotic

DNA replication?

a. The eukaryotes synthesize DNA in the three-prime to five-prime direction as well as the five-prime to three-prime direction. b. The prokaryotes have DNA polymerase while the eukaryotes do not. c. Eukaryotes do not have DNA ligase. d. Eukaryotes have multiple origins of replication and prokaryotes have just one of these.

Answer: d. The main difference between eukaryotic and prokaryotic DNA replication is that eukaryotes have multiple origins of replication, while prokaryotes have just one.

4. Which DNA replication enzyme is unique to eukaryotes?

a. DNA polymerase b. Ribonuclease H c. Helicase d. RNA primase

Answer: b. Eukaryotes have ribonuclease H, which is not present in prokaryotes. It is responsible for removing the RNA primer.

5. The making of proteins in the ribosomes is called what?

a. Replication b. Transcription c. Translation d. Post-translational modification

Answer: c. The making of proteins in the ribosomes is specifically referred to as translation. It directly follows the transcription of RNA.

6. What is the function of the poly-A tail added to messenger RNA in the nucleus?

a. To prevent degradation b. To identify the exons and introns c. To prevent degradation and to signal the need for exit of the RNA outside the nucleus d. To separate the different protein-coding segments

Answer: c. The function of the poly-A tail added to messenger RNA is to prevent degradation of the messenger RNA and to signal the need for exit of the RNA outside the nucleus.

7. What is the same thing that occurs in both prokaryotes and eukaryotes in the process of translation?

a. In both, the same start and stop codons are used. b. In both, the beginning or initiating amino acid is the same. c. In both, translation occurs simultaneously with transcription. d. In both, the same ribosomes are used.

Answer: a. The only similarity between the two is that the same start and stop codons are used. The other things are different between the two types of organisms.

8. What type of mutation in a codon leads to the same amino acid getting put into the protein?

a. Nonsense mutation b. Conditional mutation c. Missense mutation d. Silent mutation

Answer: d. A silent mutation happens when there is a mutation but it doesn’t affect the amino acid that gets put into the protein. 9. In the trp operon, what is the role of tryptophan?

a. Tryptophan itself plays no role in gene regulation. b. Tryptophan is an activator amino acid. c. Tryptophan is a repressor molecule. d. Tryptophan is an inducer molecule.

Answer: d. In this case, tryptophan is an inducer molecule that binds to a repressor molecule so that it can turn off its own synthesis in the cell when enough of it exists. The repressor molecule binds along with tryptophan to the operator region.

10. What does lactose bind to in a cell in order to trigger lactose-consuming genes in the lac operon of a eukaryotic cell?

a. Operator region b. Promotor region c. A repressor molecule d. An activator molecule

Answer: c. Lactose binds to a repressor molecule, causing it to change and fall off the operator so that the lac operon can be transcribed.