Question 1

Which of the following best describes the structure of DNA as discovered by Watson and Crick?

Accepted Answer

A double helix with antiparallel strands held together by hydrogen bonds between complementary bases.

Question 2

If a DNA sample contains 39% thymine (T), what is the percentage of cytosine (C) in the sample?

Accepted Answer

$$C = 11\%$$

Question 3

Which type of chemical bond holds the two strands of the DNA double helix together?

Accepted Answer

Hydrogen bonds

Question 4

What is meant by the term 'antiparallel' when describing DNA structure?

Accepted Answer

The two DNA strands run in opposite directions: one from $$5' to$$ $$3'$$, the other from $$3' to$$ $$5'.$$

Question 5

The Meselson-Stahl experiment provided evidence for which model of DNA replication?

Accepted Answer

Semiconservative

Question 6

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

Accepted Answer

Helicase

Question 7

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

DNA polymerase can only synthesize DNA in the $$5' \rightarrow 3'$$ direction, so the lagging strand is synthesized discontinuously.

Question 8

Which enzyme removes RNA primers and replaces them with DNA nucleotides during DNA replication?

Accepted Answer

DNA Polymerase I

Question 9

What is the role of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments together by forming phosphodiester bonds.

Question 10

Which of the following best describes the function of single-stranded binding proteins during DNA replication?

Accepted Answer

They stabilize unwound DNA strands and prevent them from reannealing.

Question 11

During DNA replication, to which end of the growing DNA strand are new nucleotides added?

Accepted Answer

$$3'$$ end

Question 12

Which molecule serves as the primer for DNA synthesis?

Accepted Answer

A short RNA strand

Question 13

Which enzyme relieves the tension ahead of the replication fork caused by unwinding of the DNA double helix?

Accepted Answer

Topoisomerase

Question 14

A mutation occurs that disables the function of nuclease enzymes in a cell. Which DNA repair process would be most directly affected?

Accepted Answer

Nucleotide excision repair

Question 15

How do eukaryotic cells address the shortening of linear DNA molecules during replication?

Accepted Answer

By adding repetitive sequences called telomeres using the enzyme telomerase.

Question 16

Which of the following is NOT a function of DNA Polymerase III during DNA replication?

Accepted Answer

Removal of RNA primers

Question 17

Which two pieces of evidence support that DNA is the genetic material?

Accepted Answer

Transformation in bacteria and Hershey-Chase experiment with bacteriophages

Question 18

A patient is exposed to UV light, causing thymine dimers in their DNA. Which DNA repair mechanism is most likely to fix this damage?

Accepted Answer

Nucleotide excision repair

Question 19

Which of the following best describes the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized in short fragments.

Question 20

During DNA replication, what determines the sequence of the daughter DNA strand?

Accepted Answer

The sequence of the template DNA strand

Chapter 16: The Molecular Basis of Inheritance -REVIEW

Study Guide - Practice Questions