$$\text{dNTP} \rightarrow \text{dNMP} + \text{PP_i}$$

Question 1

Which statement best describes the semi-conservative nature of DNA replication?

Accepted Answer

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

Question 2

During DNA synthesis in prokaryotes, what is the role of the RNA primer?

Accepted Answer

It provides a free 3' hydroxyl group for DNA polymerase to begin synthesis.

Question 3

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

DNA helicase

Question 4

In eukaryotic DNA replication, why are multiple origins of replication necessary?

Accepted Answer

Eukaryotic chromosomes are large and linear, so multiple origins allow rapid and efficient replication.

Question 5

Which of the following best explains the difference between leading and lagging strand synthesis?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously as Okazaki fragments.

Question 6

What is the function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments by sealing nicks in the sugar-phosphate backbone.

Question 7

A mutation causes the loss of an amino group from a base in DNA. What is this process called?

Accepted Answer

Deamination

Question 8

Which repair mechanism is most likely to fix a thymine dimer caused by UV radiation?

Accepted Answer

Excision repair

Question 9

In the context of DNA replication, what is the role of the 3' to 5' exonuclease activity of DNA polymerase?

Accepted Answer

It removes mismatched bases during proofreading.

Question 10

Which of the following equations correctly represents the energy released during the formation of the phosphodiester bond in DNA synthesis?

Accepted Answer

$$	ext{dNTP} ightarrow 	ext{dNMP} + 	ext{PP_i}$$

Question 11

A patient has a genetic disorder affecting the telomerase enzyme. What is the most likely cellular consequence?

Accepted Answer

Progressive shortening of chromosome ends with each cell division.

Question 12

Which of the following best describes the bidirectional nature of DNA synthesis in prokaryotes?

Accepted Answer

Replication forks move away from the origin in both directions, producing two identical circular chromosomes.

Question 13

In mismatch repair, how do enzymes distinguish the newly synthesized DNA strand from the template strand in E. coli?

Accepted Answer

By recognizing differences in DNA methylation between the parent and newly synthesized strand.

Question 14

Which of the following is a real-life example of a mutagen causing DNA damage?

Accepted Answer

Exposure to UV light causing thymine dimers.

Question 15

A scientist observes that DNA polymerase adds nucleotides only to the 3' end of a primer. What property of DNA polymerase does this illustrate?

Accepted Answer

It synthesizes DNA in the 5' to 3' direction.

Question 16

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

The lagging strand is synthesized discontinuously because DNA polymerase can only add nucleotides to the 3' end.

Question 17

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

Accepted Answer

Unwinding the DNA double helix.

Question 18

A base analog is incorporated into DNA during replication. What is the most likely outcome?

Accepted Answer

Potential mutation due to altered base pairing properties.

Question 19

Which of the following steps occurs first during DNA replication?

Accepted Answer

DNA helicase unwinds the double helix.

Question 20

A cell is exposed to a chemical that causes base modification in DNA. Which repair mechanism is most likely to be activated?

Accepted Answer

Excision repair

DNA Replication and Repair: Mechanisms and Regulation

Study Guide - Practice Questions