Question 1

Which experiment provided the first direct evidence that DNA is the genetic material in bacteria?

Accepted Answer

Avery, MacLeod, and McCarty's experiment using enzymatic treatments

Question 2

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

Accepted Answer

DNA contains phosphorus, but not sulfur; proteins contain sulfur, but not phosphorus

Question 3

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

Accepted Answer

A pentose sugar, a phosphate group, and a nitrogenous base (purine or pyrimidine)

Question 4

According to Chargaff's rules, which equation is always true for double-stranded DNA?

Accepted Answer

$$A = T$$

Question 5

What is the significance of Rosalind Franklin's X-ray crystallography photo 51?

Accepted Answer

It revealed the helical structure of DNA

Question 6

Which chemical bond joins nucleotide monomers in a DNA strand?

Accepted Answer

Phosphodiester bond

Question 7

A mutation changes a single base in a gene from adenine to guanine. Which type of base is being substituted?

Accepted Answer

Purine to purine

Question 8

Which of the following statements about prokaryotic genomes is correct?

Accepted Answer

They are usually a single, circular chromosome

Question 9

What is the basic unit of chromatin organization in eukaryotic cells?

Accepted Answer

Nucleosome

Question 10

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

Accepted Answer

DNA contains phosphate, RNA does not

Question 11

If a DNA molecule has 30% adenine, what percentage of guanine would you expect according to Chargaff's rules?

Accepted Answer

20%

Question 12

Which enzyme is responsible for relieving the stress caused by unwinding DNA during replication?

Accepted Answer

Topoisomerase

Question 13

In the context of the Central Dogma, which sequence correctly represents the flow of genetic information?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 14

Which of the following best explains why the S strain of Streptococcus pneumoniae is virulent?

Accepted Answer

It has a capsule that protects it from the immune system

Question 15

What is the distance between base pairs in the DNA double helix?

Accepted Answer

$$0.34\ nm$$

Question 16

Which of the following is a correct description of the antiparallel nature of DNA?

Accepted Answer

One strand runs 5' to 3', the other runs 3' to 5'

Question 17

Which of the following is a real-world application of understanding DNA structure?

Accepted Answer

Developing gene therapy techniques for inherited diseases

Question 18

Which base pairing is stabilized by three hydrogen bonds in DNA?

Accepted Answer

G-C

Question 19

Which of the following statements about viral genomes is correct?

Accepted Answer

Viral genomes can be DNA or RNA, single- or double-stranded, circular or linear

Question 20

A eukaryotic chromosome contains a special structure at its end called a telomere. What is the function of telomeres?

Accepted Answer

They protect chromosome ends from degradation

DNA as the Genetic Material: Historical Experiments and Molecular Structure

Study Guide - Practice Questions