Question 1

Which of the following best describes the antiparallel nature of DNA as shown in the second image?

Accepted Answer

One DNA strand runs 5' to 3' and the other runs 3' to 5'.

Question 2

During DNA replication in E. coli, which enzyme is responsible for relieving the tension generated by the unwinding of the DNA helix?

Accepted Answer

Topoisomerase

Question 3

In the process of DNA replication, what is the role of single-stranded binding proteins?

Accepted Answer

They keep the DNA strands apart and stabilize them.

Question 4

Which of the following statements about DNA polymerase III is correct?

Accepted Answer

It synthesizes DNA in the 5' to 3' direction and requires a free 3' OH group.

Question 5

A mutation occurs during DNA replication. Which enzyme's proofreading function is most likely to correct this error?

Accepted Answer

DNA polymerase III

Question 6

In the context of the replication fork, which strand is synthesized continuously and why?

Accepted Answer

The leading strand, because it is synthesized in the same direction as the movement of the replication fork.

Question 7

Which of the following sequences represents the RNA primer synthesized by primase if the DNA template sequence is 3' C C T A G G C T G C A A T C C 5' and the primer starts at the underlined T?

Accepted Answer

5' A C G U U A G G 3'

Question 8

What is the function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments together on the lagging strand.

Question 9

Which of the following best explains why multiple origins of replication are necessary in eukaryotic chromosomes?

Accepted Answer

Multiple origins speed up the replication of large, linear chromosomes.

Question 10

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand.

Question 11

If a mutation disables the proofreading function of DNA polymerase III, what is the most likely consequence?

Accepted Answer

The accuracy of DNA replication will decrease, leading to more mutations.

Question 12

Which enzyme is responsible for removing RNA primers and replacing them with DNA nucleotides during replication in E. coli?

Accepted Answer

DNA polymerase I

Question 13

Why is DNA replication considered semi-conservative?

Accepted Answer

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

Question 14

Which of the following best describes the direction in which DNA polymerase adds nucleotides during DNA synthesis?

Accepted Answer

To the 3' end in a 5' to 3' direction

Question 15

A scientist observes that DNA replication in a mutant E. coli strain is extremely slow and often incomplete. Which protein is most likely defective in this strain?

Accepted Answer

DNA polymerase III

Question 16

Which of the following is a direct result of the antiparallel structure of DNA during replication?

Accepted Answer

One strand is synthesized continuously, and the other discontinuously.

Question 17

Which of the following best explains why DNA replication is highly accurate?

Accepted Answer

Proofreading by DNA polymerase removes mismatched bases immediately after they are added.

Question 18

In a eukaryotic cell, what would be the consequence if only one origin of replication was present on a chromosome?

Accepted Answer

Replication would be much slower, possibly incomplete before cell division.

Question 19

Which of the following is NOT a function of topoisomerase during DNA replication?

Accepted Answer

Synthesizing RNA primers

Question 20

A patient is exposed to a chemical that inhibits DNA ligase. Which of the following cellular processes would be most directly affected?

Accepted Answer

Joining of Okazaki fragments on the lagging strand

DNA Replication: Mechanisms and Enzymes

Study Guide - Practice Questions

Study Guide - Flashcards