Question 1

Which enzyme is responsible for relieving the strain ahead of the replication fork during DNA replication by breaking, swiveling, and rejoining DNA strands?

Accepted Answer

Topoisomerase

Question 2

During DNA replication, which strand is synthesized continuously in the 5' to 3' direction toward the replication fork?

Accepted Answer

Leading strand

Question 3

A mutation causes the loss of function of DNA ligase in a cell. Which of the following processes would be most directly affected?

Accepted Answer

Joining Okazaki fragments on the lagging strand

Question 4

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule consists of one parental and one newly synthesized strand.

Question 5

Which of the following is NOT a function of single-strand binding proteins during DNA replication?

Accepted Answer

Synthesizing RNA primers

Question 6

A scientist exposes cells to ultraviolet light, causing thymine dimers to form. Which DNA repair process is most likely to correct this damage?

Accepted Answer

Nucleotide excision repair

Question 7

Which of the following statements about telomeres is correct?

Accepted Answer

They consist of repetitive nucleotide sequences that protect chromosome ends.

Question 8

Which enzyme synthesizes short RNA primers needed for DNA polymerase to begin DNA synthesis?

Accepted Answer

Primase

Question 9

A bacteriophage is best described as:

Accepted Answer

A virus that infects bacteria

Question 10

Which of the following best explains why the lagging strand is synthesized in fragments?

Accepted Answer

DNA polymerase can only add nucleotides to the 3' end, and the lagging strand template is oriented 5' to 3' away from the fork.

Question 11

Which of the following is a correct pairing of nitrogenous bases in DNA?

Accepted Answer

Adenine with thymine

Question 12

If a DNA molecule has 30% adenine, what percentage of guanine would you expect to find?

Accepted Answer

$$20\%$$

Question 13

Which of the following proteins is responsible for removing RNA primers and replacing them with DNA nucleotides during DNA replication?

Accepted Answer

DNA polymerase I

Question 14

Which of the following best describes euchromatin?

Accepted Answer

Less condensed chromatin that is available for transcription

Question 15

A mutation in the gene encoding helicase would most likely result in which of the following?

Accepted Answer

Inability to unwind the DNA double helix

Question 16

Which of the following is the correct order of events in nucleotide excision repair?

Accepted Answer

Nuclease cuts damaged DNA, DNA polymerase fills gap, DNA ligase seals strand

Question 17

Which of the following statements about Okazaki fragments is true?

Accepted Answer

They are joined together by DNA ligase.

Question 18

Which of the following best explains why DNA polymerase cannot initiate synthesis of a new strand?

Accepted Answer

It can only add nucleotides to an existing 3' end.

Question 19

Which of the following is a function of topoisomerase during DNA replication?

Accepted Answer

Relieving overwinding strain ahead of the replication fork

Question 20

Which of the following would most likely occur if single-strand binding proteins were nonfunctional during DNA replication?

Accepted Answer

The separated DNA strands would re-anneal before replication could occur.

DNA Structure, Replication, and Chromatin Organization

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