Question 1

Which model of DNA replication was supported by the Meselson-Stahl experiment in E. coli?

Accepted Answer

Semiconservative replication

Question 2

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

Accepted Answer

DNA helicase

Question 3

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

Accepted Answer

They stabilize the open conformation of the helix.

Question 4

Which DNA polymerase is primarily responsible for synthesizing the leading strand during eukaryotic DNA replication?

Accepted Answer

DNA polymerase ε

Question 5

Why is DNA replication discontinuous on the lagging strand?

Accepted Answer

Because the lagging strand is synthesized in short fragments called Okazaki fragments.

Question 6

What is the role of DNA ligase in DNA replication?

Accepted Answer

It joins Okazaki fragments together.

Question 7

Which protein complex recognizes origins of replication (ORIs) in eukaryotic chromosomes?

Accepted Answer

Origin Recognition Complex (ORC)

Question 8

What is the 'end replication problem' in eukaryotic cells?

Accepted Answer

The loss of DNA sequences at the ends of linear chromosomes after each round of replication.

Question 9

How is the 'end replication problem' solved in most stem cells and cancer cells?

Accepted Answer

By the activity of telomerase, which extends telomeres.

Question 10

Which enzyme removes RNA primers during eukaryotic DNA replication?

Accepted Answer

DNA polymerase δ with Flap Endonuclease I (FEN1)

Question 11

What is the function of Proliferating Cell Nuclear Antigen (PCNA) during DNA replication?

Accepted Answer

It acts as a sliding clamp to increase the processivity of DNA polymerase δ.

Question 12

Which of the following best describes the process of homologous recombination during meiosis?

Accepted Answer

Exchange of genetic material between homologous chromosomes, increasing genetic diversity.

Question 13

Which of the following equations correctly represents the addition of a nucleotide during DNA synthesis?

Accepted Answer

$$dNTP + (DNA)_{n} \rightarrow (DNA)_{n+1} + PP_i$$

Question 14

Which DNA polymerase activity allows for proofreading and error correction during DNA replication?

Accepted Answer

3' to 5' exonuclease activity

Question 15

In the context of DNA replication, what is the significance of strand polarity?

Accepted Answer

It requires DNA polymerase to synthesize the lagging strand discontinuously in Okazaki fragments.

Question 16

Which of the following statements about telomerase is TRUE?

Accepted Answer

Telomerase extends the 3' end of linear chromosomes using an RNA template.

Question 17

During DNA replication, which of the following best explains why multiple origins of replication are necessary in eukaryotes?

Accepted Answer

Eukaryotic chromosomes are linear and large, so multiple origins ensure timely replication.

Question 18

Which of the following is a direct consequence of the semiconservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule contains one parental and one newly synthesized strand.

Question 19

A mutation in the gene encoding Flap Endonuclease I (FEN1) would most likely affect which step of DNA replication?

Accepted Answer

Removal of RNA primers from Okazaki fragments

Question 20

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

Accepted Answer

It relieves supercoiling tension ahead of the replication fork.

DNA Replication and Recombination: Eukaryotic Mechanisms and Meiotic Context

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