Question 1

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

Accepted Answer

Each new DNA molecule consists of one old strand and one new strand.

Question 2

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

Accepted Answer

Helicase

Question 3

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

Accepted Answer

They prevent the separated DNA strands from re-annealing.

Question 4

In eukaryotic cells, DNA replication begins at multiple origins of replication. What is the main advantage of this?

Accepted Answer

It allows the entire genome to be replicated more quickly.

Question 5

Which enzyme synthesizes short RNA primers needed for DNA polymerase to begin synthesis?

Accepted Answer

Primase

Question 6

Why are Okazaki fragments formed during DNA replication?

Accepted Answer

Because DNA polymerase can only synthesize DNA in the 5' to 3' direction.

Question 7

Which enzyme is responsible for joining Okazaki fragments together on the lagging strand?

Accepted Answer

DNA ligase

Question 8

A mutation occurs that disables topoisomerase during DNA replication. What is the most likely consequence?

Accepted Answer

Excessive supercoiling and tension will build up ahead of the replication fork.

Question 9

In prokaryotic DNA replication, what is the shape of the DNA molecule and how does replication proceed?

Accepted Answer

Circular DNA; replication starts at a single origin and proceeds bidirectionally.

Question 10

Which of the following best explains why DNA polymerase requires a primer to begin synthesis?

Accepted Answer

DNA polymerase can only add nucleotides to an existing 3' hydroxyl group.

Question 11

If a cell is exposed to a chemical that specifically inhibits DNA ligase, which process will be most directly affected?

Accepted Answer

Joining of Okazaki fragments on the lagging strand

Question 12

Which direction does DNA polymerase synthesize new DNA?

Accepted Answer

5' to 3'

Question 13

A patient with a genetic disorder has a mutation in the gene encoding helicase. Which cellular process is most likely to be impaired?

Accepted Answer

DNA replication

Question 14

Which of the following is NOT a step in eukaryotic DNA replication?

Accepted Answer

Transcribing DNA into RNA

Question 15

During DNA replication, which strand is synthesized continuously?

Accepted Answer

Leading strand

Question 16

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

Accepted Answer

It relieves overwinding and tension ahead of the replication fork.

Question 17

If the sequence of a template DNA strand is 5'-ATGCCGTA-3', what is the sequence of the newly synthesized complementary strand?

Accepted Answer

3'-TACGGCAT-5'

Question 18

Which of the following is a real-world consequence of errors during DNA replication?

Accepted Answer

Genetic mutations that can lead to diseases such as sickle cell anemia

Question 19

A scientist is studying a new drug that inhibits primase. What effect would this drug have on DNA replication?

Accepted Answer

RNA primers would not be synthesized, preventing DNA polymerase from starting DNA synthesis.

DNA Structure and Replication: Study Notes for General Biology

Study Guide - Practice Questions