Question 1

Which experiment provided the first evidence that DNA is the hereditary material in cells?

Accepted Answer

The Griffith transformation experiment

Question 2

In the Hershey-Chase experiment, which radioactive label was found inside E. coli cells after infection with bacteriophage T2?

Accepted Answer

Radioactive phosphorus ($^{32}P$)

Question 3

Which of the following best describes the structure of DNA as determined by Watson and Crick?

Accepted Answer

A double helix with anti-parallel strands and right-handed twist

Question 4

According to Chargaff's rule, which of the following equations is correct for the base composition of DNA?

Accepted Answer

$[A] = [T]$

Question 5

What is the significance of the anti-parallel nature of DNA strands?

Accepted Answer

It enables complementary base pairing and accurate replication

Question 6

Which statement best describes semiconservative DNA replication?

Accepted Answer

Each new DNA molecule consists of one parental and one new strand

Question 7

The Meselson-Stahl experiment used $^{15}N$ and $^{14}N$ isotopes to demonstrate which concept?

Accepted Answer

DNA replication is semiconservative

Question 8

Where does DNA replication begin in prokaryotic cells?

Accepted Answer

At a single origin of replication

Question 9

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

Accepted Answer

DNA helicase

Question 10

Why is a primer required for DNA polymerase to begin synthesis?

Accepted Answer

DNA polymerase can only add nucleotides to a free 3'-OH group

Question 11

Which enzyme synthesizes the RNA primer during DNA replication?

Accepted Answer

Primase

Question 12

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

Accepted Answer

They prevent the separated DNA strands from re-annealing

Question 13

Why is DNA replication described as asymmetrical at the replication fork?

Accepted Answer

One strand is synthesized continuously, the other discontinuously

Question 14

What are Okazaki fragments?

Accepted Answer

Short DNA fragments synthesized on the lagging strand

Question 15

Which enzyme joins Okazaki fragments together during DNA replication?

Accepted Answer

DNA ligase

Question 16

What is the function of the 3' to 5' exonuclease activity of DNA polymerase?

Accepted Answer

To remove mismatched nucleotides during proofreading

Question 17

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

Accepted Answer

DNA polymerase has proofreading activity

Question 18

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

Accepted Answer

Eukaryotic chromosomes are much longer than prokaryotic chromosomes

Question 19

Which phase of the eukaryotic cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 20

A patient is exposed to UV light, causing thymine dimers in their DNA. Which DNA repair process is most likely to fix this damage?

Accepted Answer

Excision repair

DNA Structure and Replication: Foundations of Genetic Material

Study Guide - Practice Questions