Question 1

Which model of DNA replication was supported by the Meselson–Stahl experiment?

Accepted Answer

Semiconservative replication

Question 2

DNA polymerase can only add nucleotides to which end of a growing DNA strand?

Accepted Answer

$$3'$$ end

Question 3

Why is DNA synthesis considered an exergonic process?

Accepted Answer

The hydrolysis of dNTPs releases energy to drive the reaction

Question 4

Which enzyme is responsible for relieving the tension created ahead of the replication fork during DNA replication?

Accepted Answer

Topoisomerase

Question 5

What is the role of single-strand DNA-binding proteins (SSBPs) during DNA replication?

Accepted Answer

They prevent separated DNA strands from re-annealing

Question 6

Which of the following best describes the synthesis of the lagging strand during DNA replication?

Accepted Answer

It is synthesized in short fragments away from the replication fork

Question 7

What are Okazaki fragments?

Accepted Answer

Short DNA fragments synthesized on the lagging strand

Question 8

Why do eukaryotic chromosomes have multiple origins of replication?

Accepted Answer

To allow rapid and efficient replication of large genomes

Question 9

What problem arises during the replication of the ends of linear chromosomes, and how is it solved?

Accepted Answer

The lagging strand cannot be fully replicated, but telomerase extends the overhang using its RNA template

Question 10

Which cells typically express telomerase, and what is the significance of this expression?

Accepted Answer

Gametes and stem cells; it allows continued cell division

Question 11

What is the function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments together by forming phosphodiester bonds

Question 12

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

Accepted Answer

It removes incorrectly paired nucleotides using its exonuclease activity

Question 13

A mutation in the gene encoding for mismatch repair enzymes would most likely result in which of the following?

Accepted Answer

An increased rate of mutations in the genome

Question 14

Which DNA repair mechanism is specifically responsible for removing thymine dimers caused by UV light?

Accepted Answer

Nucleotide excision repair

Question 15

If a cell lacked functional primase, which process would be directly affected?

Accepted Answer

Initiation of DNA synthesis on both leading and lagging strands

Question 16

Which of the following statements about telomeres is TRUE?

Accepted Answer

They consist of short, repeating stretches of non-coding DNA

Question 17

A patient’s cells are found to have abnormally high telomerase activity. What is a possible consequence?

Accepted Answer

The cells may divide uncontrollably, increasing cancer risk

Question 18

Which of the following best explains why DNA polymerization is considered directional?

Accepted Answer

Nucleotides are always added to the $$3'$$ end of the growing strand

Question 19

Which protein is responsible for synthesizing the RNA primer during DNA replication?

Accepted Answer

Primase

Question 20

A scientist observes that a cell is unable to repair UV-induced DNA damage. Which protein complex is most likely defective?

Accepted Answer

Nucleotide excision repair complex

DNA and the Gene: Synthesis and Repair – Study Notes

Study Guide - Practice Questions