Question 1

Which of the following is NOT a requirement for a molecule to serve as genetic material in cells?

Accepted Answer

It must be able to catalyze metabolic reactions.

Question 2

Griffith's experiment with Streptococcus pneumoniae demonstrated which principle?

Accepted Answer

The transforming principle, showing that genetic material can be transferred between cells.

Question 3

Which experiment provided definitive evidence that DNA, and not protein, is the genetic material?

Accepted Answer

Hershey-Chase experiment

Question 4

What is the correct base pairing in DNA according to Watson and Crick's model?

Accepted Answer

A pairs with T, G pairs with C

Question 5

Which chemical bond links nucleotides together in a DNA strand?

Accepted Answer

Phospho-diester bond

Question 6

If a DNA molecule has 30% adenine, what percentage of guanine would you expect?

Accepted Answer

20%

Question 7

Which feature of DNA allows it to be accurately replicated?

Accepted Answer

Its double helix structure with complementary base pairing

Question 8

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

Accepted Answer

Helicase

Question 9

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

Accepted Answer

They stabilize the unwound DNA strands to prevent re-annealing.

Question 10

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

Accepted Answer

Primase

Question 11

In the Meselson-Stahl experiment, what was the key evidence supporting the semiconservative model of DNA replication?

Accepted Answer

After one round of replication, DNA had intermediate density.

Question 12

Which direction does DNA polymerase synthesize new DNA?

Accepted Answer

5' to 3'

Question 13

What is the role of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments on the lagging strand.

Question 14

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

Accepted Answer

One strand runs 5' to 3', the other runs 3' to 5'.

Question 15

A mutation occurs that prevents DNA gyrase from functioning during replication. What is the most likely consequence?

Accepted Answer

Excessive supercoiling will prevent replication fork progression.

Question 16

Which of the following equations correctly represents the number of hydrogen bonds between guanine and cytosine in DNA?

Accepted Answer

$$3$$

Question 17

If a DNA segment has the sequence 5'-ATCG-3', what is the complementary sequence?

Accepted Answer

3'-TAGC-5'

Question 18

Which enzyme removes RNA primers and replaces them with DNA nucleotides during replication?

Accepted Answer

DNA polymerase I

Question 19

Which of the following best explains why DNA replication is described as 'bi-directional'?

Accepted Answer

Replication proceeds outward in both directions from the origin.

Question 20

A patient has a genetic disorder caused by a mutation in the gene encoding DNA polymerase III. Which process would be most directly affected?

Accepted Answer

Synthesis of new DNA strands during replication

DNA Structure and Replication: Key Concepts and Mechanisms

Study Guide - Practice Questions