Question 1

Which of the following is NOT one of the four essential characteristics that a molecule must possess to serve as genetic material?

Accepted Answer

It must be able to catalyze protein synthesis directly.

Question 2

In the early 20th century, why did most scientists believe proteins, rather than DNA, were the genetic material?

Accepted Answer

Proteins are more abundant and chemically diverse than DNA.

Question 3

Frederick Griffith’s experiment with Streptococcus pneumoniae demonstrated which of the following principles?

Accepted Answer

A chemical component of cells could introduce a new, heritable trait to a cell.

Question 4

In Avery, MacLeod, and McCarty’s experiment, which enzyme treatment prevented transformation of avirulent bacteria to virulent bacteria?

Accepted Answer

DNase

Question 5

Which isotope did Hershey and Chase use to specifically label DNA in their bacteriophage experiments?

Accepted Answer

$^{32}\mathrm{P}$

Question 6

Why does DNA, but not protein, absorb ultraviolet light most strongly at 260 nm?

Accepted Answer

DNA contains aromatic bases that absorb at 260 nm.

Question 7

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 8

A scientist exposes cells to UV light at 260 nm and observes a high mutation rate. What does this suggest about the genetic material?

Accepted Answer

The genetic material absorbs maximally at 260 nm.

Question 9

Which of the following is a direct piece of evidence that DNA is the genetic material in eukaryotes?

Accepted Answer

Only DNA, not protein or RNA, can transform avirulent bacteria to virulent forms.

Question 10

In the Hershey-Chase experiment, what was the key observation that demonstrated DNA is the genetic material?

Accepted Answer

Radioactive phosphorus was found inside the bacteria after infection.

Question 11

Which of the following statements about the structure of DNA is FALSE?

Accepted Answer

The nitrogenous bases are exposed to the aqueous environment.

Question 12

Which experimental result would most strongly support the hypothesis that DNA, not protein, is the genetic material?

Accepted Answer

Transformation does not occur when DNA is destroyed by DNase.

Question 13

A mutation in the genetic material leads to a change in phenotype. Which property of genetic material does this illustrate?

Accepted Answer

Ability to allow variation by mutation

Question 14

Which of the following is an example of indirect evidence that DNA is the genetic material in eukaryotes?

Accepted Answer

The amount of DNA in gametes is half that in diploid cells.

Question 15

If a scientist treats a bacterial extract with RNase and transformation still occurs, what can be concluded?

Accepted Answer

RNA is not required for transformation.

Question 16

Which of the following best explains why $^{35}\mathrm{S}$ was used to label protein in the Hershey-Chase experiment?

Accepted Answer

Sulfur is present in proteins but not in DNA.

Question 17

Which of the following is a property of RNA that distinguishes it from DNA?

Accepted Answer

RNA is usually single-stranded.

Question 18

A scientist finds that a molecule can replicate, store information, express information, and allow variation by mutation. Which molecule is this most likely to be in a eukaryotic cell?

Accepted Answer

DNA

Question 19

Which of the following best describes the outcome when mice are injected with a mixture of heat-killed virulent bacteria and live avirulent bacteria in Griffith’s experiment?

Accepted Answer

The mice die, and live virulent bacteria can be recovered from them.

Question 20

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

Accepted Answer

Forensic DNA fingerprinting to identify individuals.

DNA Structure and Analysis: Foundations of Genetic Material

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