Question 1

Which of the following is NOT a property that the genetic material must possess to fulfill its role in living organisms?

Accepted Answer

It must be able to catalyze metabolic reactions.

Question 2

In Griffith's experiment with Streptococcus pneumoniae, what was the outcome when mice were injected with a mixture of live type R bacteria and heat-killed type S bacteria?

Accepted Answer

The mice died and type S bacteria were recovered from their blood.

Question 3

Which experimental result from Avery, MacLeod, and McCarty provided the strongest evidence that DNA is the genetic material?

Accepted Answer

Transformation was prevented by treatment with DNase.

Question 4

In the Hershey and Chase experiment, which radioactive label was found inside the E. coli cells after infection with T2 phage, and what did this indicate?

Accepted Answer

$$^{32}P$$, indicating that DNA is the genetic material.

Question 5

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

Accepted Answer

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

Question 6

Which of the following statements about the directionality of a DNA strand is correct?

Accepted Answer

The strand runs from the 5' phosphate to the 3' hydroxyl group.

Question 7

According to Chargaff's rules, if a double-stranded DNA molecule contains 30% adenine, what percentage of guanine does it contain?

Accepted Answer

$$20\%$$

Question 8

Which feature of the DNA double helix allows proteins to recognize specific sequences of bases?

Accepted Answer

The major and minor grooves on the helix.

Question 9

Which of the following best explains why DNA, and not protein, is the genetic material in most organisms?

Accepted Answer

DNA can be replicated and is capable of variation.

Question 10

Which of the following correctly describes the hydrogen bonding between bases in the DNA double helix?

Accepted Answer

Adenine forms two hydrogen bonds with thymine.

Question 11

A scientist isolates a nucleic acid and finds that it contains uracil and ribose. Which type of molecule is it?

Accepted Answer

RNA

Question 12

Which of the following best describes the difference between a nucleoside and a nucleotide?

Accepted Answer

A nucleotide contains a base, a sugar, and a phosphate group.

Question 13

Which of the following is a correct statement about the secondary structure of RNA?

Accepted Answer

RNA can form short double-helical regions due to complementary base pairing.

Question 14

If a DNA double helix is 3.4 nm long, how many complete turns does it contain? (Assume 10 base pairs per turn and 0.34 nm per base pair.)

Accepted Answer

$$1$$ complete turn

Question 15

Which of the following best explains why the two strands of DNA are described as 'antiparallel'?

Accepted Answer

One strand runs 5' to 3' and the other runs 3' to 5'.

Question 16

A mutation changes a cytosine to a thymine in a DNA molecule. According to base pairing rules, what effect will this have on the hydrogen bonding in the double helix?

Accepted Answer

It will decrease the number of hydrogen bonds from three to two at that position.

Question 17

Which of the following is a real-world application of the concept of transformation as demonstrated by Griffith's experiments?

Accepted Answer

The uptake of plasmid DNA by bacteria in genetic engineering.

Question 18

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

Accepted Answer

Alternating phosphate and sugar molecules.

Question 19

Which scientist's X-ray diffraction data was critical in determining the helical structure of DNA?

Accepted Answer

Rosalind Franklin

Question 20

Which of the following statements about the stabilization of the DNA double helix is correct?

Accepted Answer

Base stacking interactions and hydrogen bonding between complementary bases stabilize the helix.

Molecular Structure of DNA and RNA: Foundations of Genetic Material

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