Question 1

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

Accepted Answer

Semiconservative

Question 2

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

DNA helicase

Question 3

What is the primary function of DNA polymerase I in prokaryotic DNA replication?

Accepted Answer

Removing RNA primers and filling in the gaps with DNA

Question 4

Which of the following best describes the direction of DNA synthesis?

Accepted Answer

5’ to 3’

Question 5

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

Accepted Answer

They stabilize the open conformation of single-stranded DNA.

Question 6

Which enzyme relieves supercoiling ahead of the replication fork in prokaryotes?

Accepted Answer

DNA gyrase (a type of topoisomerase)

Question 7

Why is an RNA primer necessary for DNA replication?

Accepted Answer

DNA polymerase can only add nucleotides to an existing 3’ – OH group.

Question 8

Which strand is synthesized discontinuously during DNA replication, and what are the resulting fragments called?

Accepted Answer

Lagging strand; Okazaki fragments

Question 9

What is the function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments by forming phosphodiester bonds.

Question 10

Which of the following equations correctly represents the addition of a nucleotide during DNA synthesis?

Accepted Answer

$$(dNMP)_n + dNTP \xrightarrow{DNA\ polymerase} (dNMP)_{n+1} + PP_i$$

Question 11

In the Meselson-Stahl experiment, what would be the expected result after one round of replication if DNA replication were conservative?

Accepted Answer

Half DNA would be heavy, half would be light.

Question 12

Which DNA polymerase is primarily responsible for the bulk of DNA synthesis in E. coli?

Accepted Answer

DNA polymerase III

Question 13

What is the main reason eukaryotic chromosomes require telomerase activity?

Accepted Answer

To fill in the gaps left after removal of RNA primers at the ends of linear chromosomes

Question 14

Which of the following statements about proofreading during DNA replication is correct?

Accepted Answer

Proofreading is performed by the 3’ – 5’ exonuclease activity of DNA polymerases.

Question 15

A mutation in the gene encoding DNA gyrase would most likely result in which of the following problems during DNA replication?

Accepted Answer

Accumulation of supercoils ahead of the replication fork

Question 16

Which of the following best explains why eukaryotic DNA replication is more complex than prokaryotic DNA replication?

Accepted Answer

Eukaryotes have more DNA, linear chromosomes, and DNA is packaged with nucleosomes.

Question 17

Which of the following is true regarding the activity of telomerase in human cells?

Accepted Answer

Telomerase is active in stem cells and most cancer cells.

Question 18

If a mutation prevented the synthesis of RNA primers during DNA replication, which process would be directly affected?

Accepted Answer

Initiation of DNA synthesis

Question 19

Which of the following best describes a replicon?

Accepted Answer

The length of DNA replicated from a single origin of replication

Question 20

A patient’s cells are found to have abnormally short telomeres and low telomerase activity. Which of the following is a likely consequence?

Accepted Answer

Premature cellular aging and reduced cell division capacity

DNA Replication and Recombination: Study Notes for Genetics Students

Study Guide - Practice Questions