Question 1

Which experiment provided the first direct evidence that DNA is the hereditary material responsible for transformation in bacteria?

Accepted Answer

Avery, MacLeod, and McCarty's experiment with heat-killed SIII and live RII bacteria

Question 2

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

Accepted Answer

Each daughter duplex contains one parental and one newly synthesized strand.

Question 3

In the Hershey-Chase experiment, why was $$^{32}P$$ used to label DNA and $$^{35}S$$ used to label protein?

Accepted Answer

Proteins contain large amounts of sulfur, DNA contains large amounts of phosphorus.

Question 4

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

Accepted Answer

Adenine

Question 5

What is the chemical basis for complementary base pairing in the DNA double helix?

Accepted Answer

Hydrogen bonds between purines and pyrimidines

Question 6

Which enzyme is responsible for synthesizing RNA primers during DNA replication in E. coli?

Accepted Answer

Primase

Question 7

Why is DNA replication described as bidirectional in bacterial chromosomes?

Accepted Answer

Replication proceeds in both directions from a single origin.

Question 8

Which of the following best explains why the lagging strand is synthesized discontinuously?

Accepted Answer

DNA polymerase can only add nucleotides to the 3' end, and the lagging strand template is oriented 5' to 3' away from the fork.

Question 9

What is the role of DNA ligase during DNA replication?

Accepted Answer

Joins Okazaki fragments by forming phosphodiester bonds

Question 10

A mutation in the gene encoding DNA polymerase I in E. coli results in the inability to remove RNA primers. What is the most likely consequence?

Accepted Answer

Okazaki fragments will remain unjoined and contain RNA segments.

Question 11

Which of the following statements about telomerase is correct?

Accepted Answer

Telomerase extends telomeres using an RNA template.

Question 12

Which DNA form is most commonly found in living cells and has a right-handed helix with a diameter of 20 Å?

Accepted Answer

B-form

Question 13

A DNA molecule has 30% adenine. According to Chargaff's rules, what percentage of guanine would you expect?

Accepted Answer

$$20\%$$

Question 14

Which of the following best describes the function of the 3' to 5' exonuclease activity of DNA polymerase?

Accepted Answer

It removes mismatched nucleotides during proofreading.

Question 15

Which of the following is a real-world consequence of telomerase activation in somatic cells?

Accepted Answer

Increased risk of cancer due to unlimited cell division.

Question 16

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

Accepted Answer

Multiple origins allow rapid and efficient replication of large linear chromosomes.

Question 17

Which of the following is NOT a characteristic required of hereditary material?

Accepted Answer

Ability to catalyze metabolic reactions

Question 18

A researcher observes that after two rounds of DNA replication in the presence of $$^{15}N$$ and $$^{14}N$$, the DNA consists of both intermediate and light bands. Which replication model does this support?

Accepted Answer

Semiconservative

Question 19

Which of the following best describes the structure of a DNA nucleotide?

Accepted Answer

A phosphate group, a deoxyribose sugar, and a nitrogenous base

Question 20

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are short DNA segments synthesized on the lagging strand.

DNA Structure and Replication: Study Notes for Genetics Students. CH 7

Study Guide - Practice Questions

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