Question 1

Which experiment provided the first strong evidence that DNA is the genetic material by showing that traits could be transferred between bacteria?

Accepted Answer

The Griffith transformation experiment with S and R cells in mice

Question 2

According to Chargaff’s rules, if a DNA molecule contains 30% adenine, what percentage of guanine would you expect to find?

Accepted Answer

$$20\%$$

Question 3

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

Accepted Answer

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

Question 4

What is the primary function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments together on the lagging strand.

Question 5

Which enzyme relieves the strain caused by the unwinding of the DNA double helix during replication?

Accepted Answer

Topoisomerase

Question 6

Why are Okazaki fragments formed during DNA replication?

Accepted Answer

Because the lagging strand is synthesized discontinuously away from the replication fork

Question 7

Which of the following statements about hydrogen bonding in DNA is correct?

Accepted Answer

Adenine pairs with thymine via two hydrogen bonds.

Question 8

A mutation occurs that disables the proofreading function of DNA polymerase. What is the most likely consequence?

Accepted Answer

The rate of mutations during DNA replication will increase.

Question 9

Which enzyme is responsible for synthesizing short RNA primers needed to start DNA synthesis?

Accepted Answer

Primase

Question 10

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

Accepted Answer

They prevent the separated DNA strands from re-annealing.

Question 11

If a eukaryotic cell lacked functional telomerase, what would be the most likely long-term effect?

Accepted Answer

Chromosomes would gradually shorten with each cell division.

Question 12

Which of the following best explains why eukaryotic chromosomes require multiple origins of replication?

Accepted Answer

Their DNA is linear and very large, so multiple origins speed up replication.

Question 13

Which of the following is the smallest unit of DNA packaging in the nucleus?

Accepted Answer

Nucleosome

Question 14

A DNA molecule is found to have 18% cytosine. According to Chargaff’s rules, what is the percentage of adenine?

Accepted Answer

$$32\%$$

Question 15

Which enzyme is responsible for removing RNA primers and replacing them with DNA nucleotides during replication?

Accepted Answer

DNA polymerase I

Question 16

During DNA replication, which strand is synthesized continuously in the direction of the replication fork?

Accepted Answer

Leading strand

Question 17

Which of the following best describes the function of topoisomerase during DNA replication?

Accepted Answer

It relieves overwinding strain ahead of the replication fork.

Question 18

A scientist observes that after several rounds of DNA replication in a cell line, the chromosomes are becoming progressively shorter. Which enzyme is most likely defective in these cells?

Accepted Answer

Telomerase

Question 19

Which of the following is a direct result of the complementary base pairing in DNA?

Accepted Answer

Each strand of DNA can serve as a template for the synthesis of a new complementary strand.

Question 20

Which of the following best explains why C-G base pairs are more stable than A-T base pairs?

Accepted Answer

C-G pairs form three hydrogen bonds, while A-T pairs form two.

Chapter 16: The Molecular Basis of Inheritance – DNA Structure, Replication, and Chromosome Packing

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