Question 1

Which of the following statements best describes the semiconservative model of DNA replication?

Accepted Answer

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

Question 2

During DNA replication, which enzyme is responsible for synthesizing short RNA primers required for DNA polymerase to begin synthesis?

Accepted Answer

Primase

Question 3

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

Accepted Answer

After two generations, DNA consisted of both light and hybrid density strands.

Question 4

Which of the following equations correctly represents the base pairing rule in DNA?

Accepted Answer

$$A = T$$ and $$G = C$$

Question 5

A mutation causes DNA polymerase to lose its 3' to 5' exonuclease activity. What is the most likely consequence?

Accepted Answer

DNA replication will proceed faster but with increased errors.

Question 6

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 7

Why are AT-rich regions important in the origin of replication?

Accepted Answer

They are easier to separate because A-T pairs have only 2 hydrogen bonds.

Question 8

Which of the following is a function of the enzyme topoisomerase during DNA replication?

Accepted Answer

It relieves supercoiling ahead of the replication fork.

Question 9

Telomerase is essential for maintaining chromosome ends. Which of the following statements about telomerase is TRUE?

Accepted Answer

It is a ribonucleoprotein enzyme that uses an RNA template to extend telomeres.

Question 10

Which of the following best explains why most somatic cells have a limited lifespan?

Accepted Answer

Telomerase is inactive in most somatic cells, leading to progressive shortening of telomeres.

Question 11

A patient’s cancer cells are found to have highly active telomerase. What is the most likely consequence?

Accepted Answer

The cancer cells can divide indefinitely due to maintained telomere length.

Question 12

Which of the following proteins is responsible for unwinding the DNA double helix at the replication fork?

Accepted Answer

Helicase

Question 13

Which of the following is NOT a reason for the high accuracy of DNA replication?

Accepted Answer

Nucleosomes are permanently removed during replication.

Question 14

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand.

Question 15

Which of the following equations correctly represents the number of DNA molecules after $$n$$ rounds of replication, starting from one molecule?

Accepted Answer

$$2^n$$

Question 16

Which of the following is a direct consequence of the end-replication problem in linear chromosomes?

Accepted Answer

Progressive shortening of chromosomes with each cell division.

Question 17

Which enzyme catalyzes the removal of RNA primers and replaces them with DNA nucleotides in prokaryotic cells?

Accepted Answer

DNA polymerase I

Question 18

A researcher finds a cell type with highly active telomerase and rapid cell division. Which cell type is most likely being studied?

Accepted Answer

Stem cells

Question 19

Which of the following statements about DNA replication in eukaryotes is TRUE?

Accepted Answer

Multiple origins of replication are used to replicate large chromosomes efficiently.

Question 20

Which of the following proteins is responsible for stabilizing single-stranded DNA during replication?

Accepted Answer

Single-strand binding proteins (SSB)

DNA Replication: Mechanisms, Models, and Enzymes

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