Question 1

Which of the following best describes the phenomenon observed in Griffith's experiment with Streptococcus pneumoniae?

Accepted Answer

Mixing heat-killed pathogenic bacteria with living nonpathogenic bacteria resulted in the nonpathogenic bacteria becoming pathogenic.

Question 2

In the Hershey-Chase experiment, which radioactive label was found inside the bacterial cells after infection by bacteriophage?

Accepted Answer

Radioactive phosphorus ($$^{32}P)$$

Question 3

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

Accepted Answer

20%

Question 4

Which scientist(s) used X-ray diffraction to help reveal the structure of DNA?

Accepted Answer

Rosalind Franklin

Question 5

What is the significance of the antiparallel arrangement of DNA strands in the double helix?

Accepted Answer

It permits complementary base pairing and accurate replication.

Question 6

During DNA replication, which enzyme is responsible for relieving the strain caused by unwinding of the DNA double helix?

Accepted Answer

Topoisomerase

Question 7

Which of the following statements about DNA polymerase is correct?

Accepted Answer

It adds nucleotides to the 3' hydroxyl group of the growing DNA strand.

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 two template strands are antiparallel.

Question 9

Which enzyme is responsible for joining Okazaki fragments together on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 10

A mutation in which enzyme would most likely result in a significantly increased mutation rate during DNA replication?

Accepted Answer

DNA polymerase (proofreading function)

Question 11

What is the function of telomerase in eukaryotic cells?

Accepted Answer

It catalyzes the lengthening of telomeres, preventing chromosome shortening.

Question 12

Which of the following is a direct consequence of telomere shortening in somatic cells?

Accepted Answer

Cells age and eventually stop dividing.

Question 13

Which of the following best describes the semi-conservative model of DNA replication demonstrated by the Meselson-Stahl experiment?

Accepted Answer

Each new DNA molecule consists of one old (parental) strand and one new strand.

Question 14

If a DNA strand has the sequence 5'-AATGCTAC-3', what is the sequence of the complementary strand?

Accepted Answer

3'-TTACGATG-5'

Question 15

Which of the following enzymes is responsible for removing RNA primers and replacing them with DNA nucleotides during DNA replication?

Accepted Answer

DNA polymerase I

Question 16

Which of the following statements about the origin of replication (ORI) is correct?

Accepted Answer

Eukaryotes have multiple ORIs per chromosome.

Question 17

Which of the following is NOT a function of single-stranded binding proteins (SSBs) during DNA replication?

Accepted Answer

Synthesizing new DNA strands.

Question 18

Which of the following facts did Hershey and Chase use to distinguish between DNA and protein as the genetic material?

Accepted Answer

DNA contains phosphorus, whereas protein does not.

Question 19

Which of the following is a correct match between enzyme and function in DNA replication?

Accepted Answer

Primase - provides short stretch of RNA at initiation of strand synthesis

Question 20

Which of the following is involved in replicating the lagging strand of DNA, but is not involved in leading strand replication?

Accepted Answer

Okazaki fragments

DNA Synthesis: Experiments, Structure, and Replication

Study Guide - Practice Questions