Q: Which equation correctly represents the direction of DNA polymerase synthesis relative to the template strand?

$$\text{DNA pol synthesizes: 5' \rightarrow 3' relative to template strand}$$

Q: Which equation represents the error rate of DNA polymerase after proofreading?

$$\text{Error rate} \u003c 1 \text{ in } 10^8$ \text{ nucleotides}$$

Question 1

Which of the following best explains why the ends of eukaryotic chromosomes shorten with each round of DNA replication?

Accepted Answer

The removal of the RNA primer from the lagging strand leaves a gap that cannot be filled by DNA polymerase.

Question 2

What is the primary function of telomerase in eukaryotic cells?

Accepted Answer

To extend the parental DNA strand using an RNA template, preventing chromosome shortening.

Question 3

Which equation correctly represents the direction of DNA polymerase synthesis relative to the template strand?

Accepted Answer

$$	ext{DNA pol synthesizes: 5' ightarrow 3' relative to template strand}$$

Question 4

Which component of the telomerase complex is encoded by the TERT gene?

Accepted Answer

The protein enzyme responsible for reverse transcription

Question 5

A mutation in the TERC gene would most likely affect which aspect of telomerase function?

Accepted Answer

The sequence of the RNA template used to extend telomeres

Question 6

Which of the following is a consequence of thymidine dimer formation due to UV radiation?

Accepted Answer

Formation of a cyclobutane ring that distorts the DNA double helix

Question 7

Which repair mechanism is primarily responsible for correcting mismatches that occur during DNA replication?

Accepted Answer

Mismatch repair (MMR)

Question 8

In bacteria, how does the mismatch repair (MMR) machinery distinguish the newly synthesized strand from the template strand?

Accepted Answer

By detecting methylation patterns and timing of methylation

Question 9

Which of the following best describes the role of DNA polymerase proofreading activity?

Accepted Answer

It uses a 3'-5' exonuclease activity to correct errors, reducing the error rate to less than 1 in 100 million nucleotides.

Question 10

Which equation represents the error rate of DNA polymerase after proofreading?

Accepted Answer

$$	ext{Error rate} \u003c 1 	ext{ in } 10^8$ 	ext{ nucleotides}$$

Question 11

Which of the following is NOT a mechanism for repairing single-strand DNA damage?

Accepted Answer

Homologous recombination (HR)

Question 12

What is the main difference between induced and spontaneous DNA damage?

Accepted Answer

Induced damage is caused by external factors like UV radiation, while spontaneous damage is due to intrinsic chemical instability.

Question 13

Which of the following is a real-world example of induced DNA damage?

Accepted Answer

Formation of thymidine dimers from UV exposure

Question 14

Which equation best describes the relationship between telomere length and cell division?

Accepted Answer

$$	ext{Telomere length decreases as the number of cell divisions increases}$$

Question 15

Which of the following statements about telomerase expression in human cells is correct?

Accepted Answer

Telomerase expression is developmentally regulated and is active in most tissues during embryonic development, but turns off in most adult cells except stem and germline cells.

Question 16

Which of the following is a plausible outcome if DNA polymerase could synthesize DNA in the 3' to 5' direction?

Accepted Answer

Both strands could be synthesized continuously, eliminating the need for Okazaki fragments.

Question 17

Which of the following best describes the process of reverse transcription performed by telomerase?

Accepted Answer

Telomerase uses an RNA template to synthesize DNA.

Question 18

Which of the following is a permanent chemical change in double-stranded DNA?

Accepted Answer

Mutation

Question 19

Which of the following is a plausible reason why telomerase is a target for experimental cancer immunotherapy?

Accepted Answer

Telomerase is critical for the survival of most tumor cells and is rarely expressed in normal somatic cells.

Lesson 5: Telomerase, DNA Replication, and DNA Damage

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