Question 1

Which of the following best describes the antiparallel nature of DNA strands?

Accepted Answer

One strand runs 5' to 3' and the other runs 3' to 5'.

Question 2

If a DNA molecule is composed of 30% adenine, what percentage of guanine would you expect to find?

Accepted Answer

$20\%$

Question 3

Which enzyme is responsible for relieving the strain ahead of the replication fork during DNA replication?

Accepted Answer

Topoisomerase

Question 4

What type of bond connects the sugar and phosphate groups in the DNA backbone?

Accepted Answer

Covalent bond

Question 5

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are joined together by DNA ligase.

Question 6

During DNA replication, which enzyme adds nucleotides to the 3' end of the new strand?

Accepted Answer

DNA polymerase

Question 7

Which base pairing is stabilized by three hydrogen bonds?

Accepted Answer

Guanine–Cytosine

Question 8

What is the role of single-strand binding proteins (SSBP) during DNA replication?

Accepted Answer

They keep the DNA strands separated and untwisted.

Question 9

Which of the following best explains why hydrogen bonds between base pairs are important for DNA function?

Accepted Answer

They allow the DNA strands to separate easily during replication.

Question 10

A mutation causes DNA polymerase to lose its proofreading ability. What is the most likely consequence?

Accepted Answer

Increased frequency of mutations

Question 11

Which of the following is a difference between DNA and RNA?

Accepted Answer

DNA is usually double-stranded, RNA is usually single-stranded.

Question 12

Which enzyme removes RNA primers during DNA replication?

Accepted Answer

DNA polymerase I

Question 13

A scientist exposes cells to ultraviolet light, causing thymine dimers. Which repair enzyme is most likely to be involved in correcting this damage?

Accepted Answer

Exonuclease

Question 14

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

Accepted Answer

Each new DNA molecule consists of one parental and one new strand.

Question 15

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 16

Which of the following is true about the direction of new DNA strand synthesis?

Accepted Answer

It is synthesized in the 5' to 3' direction.

Question 17

What would happen if DNA ligase were nonfunctional during replication?

Accepted Answer

Okazaki fragments would not be joined together.

Question 18

Which of the following is a purine base found in DNA?

Accepted Answer

Adenine

Question 19

A DNA strand has the sequence 5'-ATCGGCTA-3'. What is the complementary sequence?

Accepted Answer

3'-TAGCCGAT-5'

Question 20

Which of the following best explains why multiple origins of replication are necessary in eukaryotic cells?

Accepted Answer

Eukaryotic chromosomes are large and linear, requiring multiple starting points for efficient replication.

DNA Structure and Replication: A Comprehensive Study Guide

Study Guide - Practice Questions