Question 1

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

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Question 2

During DNA synthesis, which type of chemical bond is formed between nucleotides?

Accepted Answer

Phosphodiester bond between the 3' end of the growing strand and the 5' end of the incoming nucleotide

Question 3

What is the primary function of helicase during DNA replication?

Accepted Answer

Unwinds and separates the DNA strands at the replication fork

Question 4

Why does DNA polymerase require a primer to begin synthesis?

Accepted Answer

It cannot initiate synthesis without a free 3' hydroxyl group

Question 5

Which enzyme relieves the twisting pressure in double-stranded DNA ahead of the replication fork?

Accepted Answer

Topoisomerase

Question 6

In eukaryotic cells, why does DNA shorten with each round of replication?

Accepted Answer

DNA polymerase cannot complete the 5' end of the lagging strand due to the need for a primer

Question 7

What is the role of telomerase in eukaryotic cells?

Accepted Answer

It extends chromosome ends by adding telomere sequence repeats using its own RNA template

Question 8

Which of the following best explains why bacterial DNA does not lose genetic material during replication?

Accepted Answer

Bacterial DNA is circular, so there are no ends to lose genetic material from

Question 9

Which statement about Okazaki fragments is correct?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand, each preceded by an RNA primer

Question 10

Which enzyme is responsible for joining Okazaki fragments together during DNA replication?

Accepted Answer

DNA ligase

Question 11

What is the direction of new DNA strand synthesis by DNA polymerase?

Accepted Answer

5' to 3'

Question 12

Which of the following is a real-world consequence of telomerase reactivation in human cells?

Accepted Answer

It contributes to the immortality of many cancer cells

Question 13

A mutation disables primase in a cell. What is the most immediate effect on DNA replication?

Accepted Answer

DNA polymerase will be unable to initiate DNA synthesis due to lack of RNA primers

Question 14

Which of the following best describes the energy source for DNA synthesis?

Accepted Answer

Hydrolysis of the incoming nucleoside triphosphate (dNTP)

Question 15

Why do eukaryotic chromosomes have multiple origins of replication?

Accepted Answer

To allow faster and more efficient replication of large genomes

Question 16

Which of the following enzymes is NOT directly involved in lagging strand synthesis?

Accepted Answer

Topoisomerase

Question 17

A cell is observed to have abnormally short telomeres and enters cell senescence. Which process is most likely impaired?

Accepted Answer

Telomerase activity

Question 18

Which of the following is a constraint of DNA polymerase during replication?

Accepted Answer

It can only add nucleotides to the 3' end of a primer

Question 19

Which of the following best explains the role of single-strand binding proteins (SSBPs) during DNA replication?

Accepted Answer

They stabilize separated DNA strands to prevent re-annealing

Question 20

Which formula correctly represents the direction of DNA polymerase movement along the template strand?

Accepted Answer

$$	ext{DNA polymerase moves along the template strand from 3' ightarrow 5'}$$

DNA Structure and Replication: Mechanisms, Enzymes, and Telomere Maintenance

Study Guide - Practice Questions