DNA Replication: A Comprehensive Guide for Biotechnology Students

Question 1

During DNA replication, which enzyme is responsible for unwinding the DNA double helix, separating its two strands?

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

DNA ligase

Question 2

In DNA replication, which enzyme synthesizes new DNA strands by adding nucleotides to the 3'-OH end of the growing chain?

Accepted Answer

DNA polymerase III

Answer

DNA polymerase I

Answer

RNA polymerase

Answer

Helicase

Question 3

Which enzyme is primarily responsible for synthesizing new DNA strands during replication?

Accepted Answer

DNA polymerase III

Answer

RNA polymerase

Answer

Ligase

Answer

Primase

Question 4

What is the primary function of the primer in DNA replication?

Accepted Answer

To provide a 3' hydroxyl group for DNA polymerase to start DNA synthesis

Answer

To stabilize the single-stranded DNA template

Answer

To terminate DNA synthesis

Answer

To proofread newly synthesized DNA

Question 5

Which of the following is NOT a characteristic of DNA replication?

Accepted Answer

Requires RNA primers on both strands

Answer

Semi-conservative

Answer

Bidirectional

Answer

Catalyzed by DNA polymerase

Question 6

On the leading strand during replication, in which direction does DNA polymerase synthesize DNA?

Accepted Answer

5' to 3'

Answer

3' to 5'

Answer

Continuously

Answer

Discontinuously

Question 7

What consequence arises from the antiparallel nature of DNA strands during replication?

Accepted Answer

The leading and lagging strands are synthesized in opposite directions

Answer

Replication can occur continuously on both strands

Answer

DNA polymerases require primers on both strands

Answer

Okazaki fragments are produced only on the leading strand

Question 8

What is the specific role of ligase in DNA replication?

Accepted Answer

Joining Okazaki fragments on the lagging strand

Answer

Removing RNA primers from newly synthesized DNA

Answer

Unwinding the DNA double helix ahead of the replication fork

Answer

Proofreading newly synthesized DNA

Question 9

What is the primary significance of telomeres in DNA replication?

Accepted Answer

Protecting the ends of chromosomes from degradation

Answer

Serving as primers for DNA polymerase

Answer

Regulating the length of chromosomes

Answer

Preventing the replication of non-coding DNA

Question 10

Which molecular mechanisms serve as checkpoints to maintain the fidelity of DNA replication?

Accepted Answer

Checkpoint proteins and repair enzymes

Answer

Primase and helicase

Answer

DNA polymerase and DNA ligase

Answer

Ribonuclease H and topoisomerase

Question 11

Which enzyme is responsible for breaking the hydrogen bonds between DNA strands during DNA replication?

Accepted Answer

Helicase

Answer

Polymerase

Answer

Primase

Answer

Ligase

Question 12

Which of the following is a key feature of semi-conservative DNA replication?

Accepted Answer

Each daughter molecule is composed of one original and one newly synthesized DNA strand

Answer

Okazaki fragments are produced on the leading strand

Answer

DNA replication is carried out by RNA polymerase

Answer

Replication occurs only in the 5' to 3' direction on both strands.

Question 13

What is the primary function of primase in DNA replication?

Accepted Answer

To synthesize short RNA primers that provide a starting point for DNA polymerase

Answer

To join Okazaki fragments together

Answer

To unwind the DNA double helix

Question 14

Which of the following DNA polymerases is primarily responsible for synthesizing the majority of the new DNA strand during replication?

Accepted Answer

DNA polymerase III

Answer

RNA polymerase

Answer

DNA polymerase I

Answer

DNA polymerase II

Question 15

What is the purpose of DNA ligase in DNA replication?

Accepted Answer

To covalently join Okazaki fragments on the lagging strand into a continuous DNA strand

Answer

To correct errors in the newly synthesized DNA strand

Answer

To remove RNA primers from the newly synthesized DNA strand

Question 16

What is the significance of telomeres in DNA replication?

Accepted Answer

To prevent the progressive shortening of chromosomes with each cell division

Answer

To repair damaged DNA

Answer

To initiate DNA replication

Answer

To encode essential genes for cellular function

Question 17

Which molecular biology technique is commonly used to amplify specific regions of DNA for research or diagnostic purposes?

Accepted Answer

PCR (Polymerase Chain Reaction)

Answer

Southern blotting

Answer

DNA sequencing

Answer

Gel electrophoresis

Question 18

What is the ultimate outcome of DNA replication?

Accepted Answer

The production of two identical copies of the original DNA molecule

Answer

The repair of damaged DNA

Answer

The synthesis of new RNA molecules

Answer

The recombination of genetic material

Question 19

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

Accepted Answer

Helicase

Answer

DNA polymerase

Answer

Ligase

Answer

Topoisomerase

Question 20

How is the leading strand synthesized during DNA replication?

Accepted Answer

Continuously in the 5' to 3' direction.

Answer

In the 3' to 5' direction.

Answer

Discontinuously in the 5' to 3' direction.

Question 21

Which of the following is NOT a requirement for DNA polymerase to begin replicating DNA?

Accepted Answer

A primer with a 5' phosphate group

Answer

Deoxynucleotide triphosphates (dNTPs)

Answer

A template strand

Answer

A free 3' hydroxyl group

Question 22

What is the purpose of Okazaki fragments in DNA replication?

Accepted Answer

They are short DNA segments synthesized on the lagging strand.

Answer

They are involved in unwinding the DNA helix.

Answer

They serve as starting points for DNA polymerase activity.

Question 23

What is the primary function of DNA ligase during DNA replication?

Accepted Answer

Joining Okazaki fragments together on the lagging strand.

Answer

Unwinding the DNA double helix.

Answer

Adding nucleotides to the growing DNA strand.

Question 24

Why is a primer necessary for DNA polymerase to begin replication?

Accepted Answer

To provide a free 3' hydroxyl group for DNA polymerase to add nucleotides to.

Answer

To prevent the DNA from unwinding.

Answer

To separate the DNA strands.

Question 25

Why is DNA replication described as semi-conservative?

Accepted Answer

Each newly formed DNA molecule contains one original strand and one newly synthesized strand.

Answer

The original DNA molecule is completely preserved during replication.

Answer

The new DNA molecules are identical to the original molecule.

Question 26

During DNA replication, which enzyme is responsible for removing RNA primers?

Accepted Answer

DNA polymerase I

Answer

DNA polymerase III

Answer

Helicase

Answer

Ligase

Question 27

What is the primary reason for the high accuracy of DNA replication?

Accepted Answer

The proofreading activity of DNA polymerase.

Answer

The rapid rate of replication.

Answer

The presence of multiple origins of replication.

Answer

The use of RNA primers.