Question 1

Which of the following statements best explains why DNA is considered the genetic material in cells?

Accepted Answer

DNA is a polymer of nucleotides, each consisting of a nitrogenous base, a sugar, and a phosphate group.

Question 2

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

Accepted Answer

Helicase

Question 3

What is the main function of single-strand binding proteins during DNA replication?

Accepted Answer

They bind to and stabilize single-stranded DNA.

Question 4

Which of the following best describes the antiparallel nature of DNA?

Accepted Answer

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

Question 5

Which enzyme synthesizes the short RNA primer required for DNA polymerase to begin DNA synthesis?

Accepted Answer

Primase

Question 6

Why is the lagging strand synthesized in short fragments during DNA replication?

Accepted Answer

DNA polymerase must work away from the replication fork, resulting in Okazaki fragments.

Question 7

What is the role of DNA ligase in DNA replication?

Accepted Answer

It joins Okazaki fragments together on the lagging strand.

Question 8

Which of the following models of DNA replication was supported by experimental evidence?

Accepted Answer

Semiconservative model

Question 9

What is the evolutionary significance of mutations that occur during DNA replication?

Accepted Answer

They are the source of genetic variation upon which natural selection operates.

Question 10

Why do eukaryotic chromosomes have telomeres at their ends?

Accepted Answer

To postpone the erosion of genes near the ends of DNA molecules.

Question 11

Which enzyme catalyzes the lengthening of telomeres in germ cells?

Accepted Answer

Telomerase

Question 12

What is the main difference between dATP and ATP?

Accepted Answer

dATP has deoxyribose, while ATP has ribose.

Question 13

Which process is responsible for correcting errors in base pairing during DNA replication?

Accepted Answer

Mismatch repair

Question 14

What is the consequence of repeated rounds of DNA replication in eukaryotic cells without telomerase activity?

Accepted Answer

Essential genes may eventually be lost from the ends of chromosomes.

Question 15

Which of the following best describes the function of topoisomerase during DNA replication?

Accepted Answer

It relieves the strain caused by unwinding the DNA double helix.

Question 16

A mutation occurs during DNA replication and is not repaired. What is the most likely long-term consequence?

Accepted Answer

The mutation may become permanent and be passed on to future generations.

Question 17

Which of the following equations correctly represents the loss of phosphate groups during the addition of a nucleotide to a growing DNA strand?

Accepted Answer

$$dNTP \rightarrow dNMP + 2P_i$$

Question 18

In nucleotide excision repair, which enzyme is responsible for removing the damaged DNA segment?

Accepted Answer

Nuclease

Question 19

Which of the following best explains why cancer cells often have high telomerase activity?

Accepted Answer

To allow unlimited cell divisions by maintaining telomere length.

Question 20

A scientist observes that a eukaryotic cell has multiple replication bubbles during DNA synthesis. What does this indicate about the chromosome?

Accepted Answer

It is linear and has multiple origins of replication.

Chapter 16: The Molecular Basis of Inheritance

Study Guide - Practice Questions