Question 1

Which experiment provided the strongest evidence that DNA, and not protein, is the genetic material in cells?

Accepted Answer

The Hershey-Chase experiment

Question 2

What is the main function of DNA polymerase during DNA replication?

Accepted Answer

To add deoxyribonucleotides to the growing DNA strand in the 5' → 3' direction

Question 3

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 4

During DNA replication, which enzyme is responsible for relieving the strain caused by unwinding the double helix?

Accepted Answer

Topoisomerase

Question 5

Why are Okazaki fragments formed during DNA replication?

Accepted Answer

Because the lagging strand is synthesized discontinuously in short segments

Question 6

Which enzyme joins Okazaki fragments together to form a continuous DNA strand?

Accepted Answer

DNA ligase

Question 7

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

Accepted Answer

They stabilize and protect single-stranded DNA

Question 8

In the Meselson-Stahl experiment, what was the significance of using $$^{15}N$$ and $$^{14}N$$ isotopes?

Accepted Answer

To differentiate between old and newly synthesized DNA strands

Question 9

Which of the following is NOT a basic rule of DNA replication?

Accepted Answer

Synthesis occurs in the 3' → 5' direction

Question 10

What is the function of telomerase in eukaryotic cells?

Accepted Answer

It adds repetitive DNA sequences to the ends of chromosomes

Question 11

Which of the following mechanisms is responsible for the high accuracy of DNA replication?

Accepted Answer

Proofreading activity of DNA polymerase

Question 12

A mutation damages a cell's ability to produce primase. Which process would be directly affected?

Accepted Answer

Synthesis of RNA primers for DNA replication

Question 13

Which of the following best explains why eukaryotic chromosomes have multiple origins of replication?

Accepted Answer

Multiple origins speed up the replication of large, linear chromosomes

Question 14

Which enzyme removes RNA primers and replaces them with DNA nucleotides during lagging strand synthesis?

Accepted Answer

DNA polymerase I

Question 15

A patient is exposed to high levels of UV radiation, causing DNA damage. Which repair mechanism is most likely to be activated?

Accepted Answer

Nucleotide excision repair

Question 16

Which of the following statements about the directionality of DNA synthesis is correct?

Accepted Answer

DNA is synthesized in the 5' → 3' direction

Question 17

If a mutation prevents the formation of single-strand binding proteins, what is the most likely consequence during DNA replication?

Accepted Answer

Single-stranded DNA will re-anneal or degrade, halting replication

Question 18

Which of the following best describes the role of hydrogen bonding in DNA replication accuracy?

Accepted Answer

Hydrogen bonds stabilize correct base pairs, reducing errors

Question 19

Why is the shortening of telomeres significant in cellular aging?

Accepted Answer

It leads to the loss of essential genes from chromosomes

Question 20

Which of the following is a direct result of the dehydration reaction during DNA polymerization?

Accepted Answer

Release of two phosphate groups as pyrophosphate

DNA Structure and Replication: Study Notes

Study Guide - Practice Questions