Question 1

Which experiment provided the strongest evidence that DNA, and not protein, is the genetic material in phages that infect bacteria?

Accepted Answer

Hershey and Chase's experiment using radioactive isotopes to label DNA and protein in T2 phages

Question 2

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

Accepted Answer

$$20\%$$

Question 3

Which of the following best explains why pairing a purine with a pyrimidine in the DNA double helix results in a uniform width?

Accepted Answer

Purines are larger, and pairing with smaller pyrimidines maintains a constant helix diameter.

Question 4

Which enzyme is responsible for relieving the strain caused by unwinding the DNA double helix during replication?

Accepted Answer

Topoisomerase

Question 5

During DNA replication, why is an RNA primer necessary?

Accepted Answer

DNA polymerase can only add nucleotides to an existing 3' end.

Question 6

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are joined together by DNA ligase.

Question 7

A mutation occurs during DNA replication, but the error is corrected before cell division. Which process most likely fixed the error?

Accepted Answer

Mismatch repair

Question 8

Why do eukaryotic chromosomes have multiple origins of replication?

Accepted Answer

Their DNA molecules are long and linear, requiring multiple starting points for efficient replication.

Question 9

What is the main function of telomeres in eukaryotic chromosomes?

Accepted Answer

To postpone the erosion of genes near the ends of DNA molecules

Question 10

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 newly synthesized strand.

Question 11

Which protein is responsible for synthesizing the RNA primer during DNA replication?

Accepted Answer

Primase

Question 12

A scientist observes that a certain region of chromatin is highly condensed and transcriptionally inactive. What is this region most likely called?

Accepted Answer

Heterochromatin

Question 13

Which of the following is a direct consequence of the antiparallel structure of DNA?

Accepted Answer

One strand is synthesized continuously, while the other is synthesized in fragments.

Question 14

Which of the following best explains why mutations are important for evolution?

Accepted Answer

They are the source of genetic variation upon which natural selection acts.

Question 15

Which of the following statements about nucleosomes is correct?

Accepted Answer

They are composed of DNA wrapped around a core of eight histone proteins.

Question 16

A patient is exposed to X-rays, which cause DNA damage. Which repair mechanism is most likely to remove and replace the damaged DNA segment?

Accepted Answer

Nucleotide excision repair

Question 17

Which of the following is true regarding the function of DNA ligase during replication?

Accepted Answer

It joins Okazaki fragments on the lagging strand.

Question 18

Which of the following best describes the role of histone tails in chromatin?

Accepted Answer

They are involved in the regulation of gene expression through chemical modifications.

Question 19

If a eukaryotic cell lost the function of telomerase, what would be the most likely long-term consequence?

Accepted Answer

Chromosomes would gradually shorten, potentially leading to loss of essential genes.

Question 20

Which of the following statements about the bacterial chromosome is correct?

Accepted Answer

It is circular and found in the nucleoid region.

Chapter 16: The Molecular Basis of Inheritance – Study Notes

Study Guide - Practice Questions