Question 1

Which experiment provided the first strong evidence that DNA, and not protein, is the genetic material in cells?

Accepted Answer

Hershey and Chase’s bacteriophage labeling experiment

Question 2

Which of the following best describes the structure of a DNA double helix as proposed by Watson and Crick?

Accepted Answer

Two antiparallel strands with sugar-phosphate backbone on the outside and paired bases on the inside

Question 3

Which chemical component is found in DNA but not in proteins, and was used by Hershey and Chase to distinguish DNA from protein?

Accepted Answer

Phosphorus

Question 4

What is the significance of Chargaff’s rules in understanding DNA structure?

Accepted Answer

They demonstrated that the amount of adenine equals thymine and guanine equals cytosine in DNA

Question 5

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA contains phosphate, RNA does not

Question 6

A mutation changes a single base in a gene from A to G. Which of the following is the most direct molecular consequence?

Accepted Answer

A change in the sequence of RNA transcribed from the gene

Question 7

Which enzyme would relieve the stress caused by unwinding DNA during replication in prokaryotes?

Accepted Answer

Topoisomerase

Question 8

What is the basic repeating unit (monomer) of DNA and RNA?

Accepted Answer

Nucleotide

Question 9

Which of the following best explains why DNA can serve as a template for its own replication?

Accepted Answer

The sequence of bases on one strand determines the sequence on the other by complementary base pairing

Question 10

Which of the following statements about nucleosomes is correct?

Accepted Answer

Each nucleosome contains 146 base pairs of DNA wrapped around eight histone proteins

Question 11

A virus is found to have a genome composed of single-stranded RNA. Which of the following statements is true?

Accepted Answer

Some viruses can have RNA genomes, which may be single- or double-stranded

Question 12

Which of the following best describes the polarity of a DNA strand?

Accepted Answer

One end has a free phosphate group (5’ end) and the other has a free hydroxyl group (3’ end)

Question 13

Which of the following is a real-world application of the discovery that DNA is the genetic material?

Accepted Answer

Gene therapy for inherited diseases

Question 14

Which of the following bonds joins nucleotide monomers together in a DNA strand?

Accepted Answer

Phosphodiester bonds

Question 15

Which of the following best explains why the S strain of Streptococcus pneumoniae is virulent while the R strain is not?

Accepted Answer

The S strain has a protective capsule that prevents destruction by the host immune system

Question 16

Which of the following is a direct result of the antiparallel orientation of DNA strands?

Accepted Answer

The 5’ end of one strand aligns with the 3’ end of the other

Question 17

Which of the following is a correct statement about the major and minor grooves of DNA?

Accepted Answer

They are formed by the twisting of the double helix and are important for protein binding

Question 18

Which of the following best describes the role of Rosalind Franklin’s X-ray crystallography in the discovery of DNA structure?

Accepted Answer

It provided evidence for the helical structure of DNA

Question 19

Which of the following is a property of prokaryotic genomes?

Accepted Answer

They are usually a single, circular chromosome with possible plasmids

Question 20

Which of the following is a correct description of a gene according to the molecular definition?

Accepted Answer

A segment of DNA that contains the genetic information to express a protein

DNA as the Genetic Material: Structure, Evidence, and Organization

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