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

Question 1

Which property is NOT required for a molecule to serve as genetic material in cells?

Accepted Answer

It must be able to catalyze metabolic reactions.

Question 2

What is the significance of complementary base pairing in the Watson-Crick model of DNA?

Accepted Answer

It enables each strand to serve as a template for accurate replication.

Question 3

Which experiment provided strong evidence for the semi-conservative model of DNA replication?

Accepted Answer

Meselson-Stahl experiment

Question 4

After one round of DNA replication in the Meselson-Stahl experiment, what was observed in the CsCl density gradient?

Accepted Answer

A single band of intermediate (hybrid) DNA

Question 5

Which enzyme is responsible for joining Okazaki fragments during lagging strand synthesis?

Accepted Answer

DNA ligase

Question 6

What is the direction of DNA synthesis by DNA polymerases?

Accepted Answer

5' to 3'

Question 7

Which activity allows DNA polymerase to correct errors during DNA replication?

Accepted Answer

3' to 5' exonuclease activity

Question 8

Why do eukaryotic chromosomes require telomeres?

Accepted Answer

To protect chromosome ends from loss during replication

Question 9

Which enzyme is responsible for adding repeated DNA sequences to the ends of eukaryotic chromosomes?

Accepted Answer

Telomerase

Question 10

In E. coli, where does DNA replication begin?

Accepted Answer

At a single fixed site called oriC

Question 11

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

Accepted Answer

They keep the template strands separated.

Question 12

Which of the following is TRUE about the lagging strand during DNA replication?

Accepted Answer

It is synthesized in short fragments called Okazaki fragments.

Question 13

Which equation best represents the formation of a phosphodiester bond during DNA synthesis?

Accepted Answer

$$	ext{dNTP} + (DNA)_{n} ightarrow (DNA)_{n+1} + PP_i$$

Question 14

Which model of DNA replication was ruled out after the first round of the Meselson-Stahl experiment?

Accepted Answer

Conservative replication

Question 15

What is the role of primase during DNA replication?

Accepted Answer

It synthesizes a short RNA primer.

Question 16

Which of the following statements about DNA polymerase is FALSE?

Accepted Answer

It can synthesize DNA de novo without a primer.

Question 17

Why are purine-pyrimidine base pairs 'just right' for DNA structure?

Accepted Answer

They are the same size, maintaining uniform width of the double helix.

Question 18

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

Accepted Answer

Each daughter DNA molecule contains one old strand and one new strand.

Question 19

What is the function of topoisomerase during DNA replication?

Accepted Answer

It removes supercoils introduced by DNA replication.

Question 20

Which of the following is a real-world consequence of telomere shortening in human cells?

Accepted Answer

Cellular aging and senescence due to loss of protective 'junk' DNA.

DNA Replication: Mechanisms, Enzymes, and Experimental Evidence

Study Guide - Practice Questions