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

Ability to catalyze metabolic reactions

Question 2

In the Hershey-Chase experiment, which radioactive isotope was used to label DNA, and what was the main conclusion of the experiment?

Accepted Answer

$^{32}\mathrm{P}$; DNA is the genetic material in bacteria

Question 3

Which of the following statements about the structure of DNA proposed by Watson and Crick is FALSE?

Accepted Answer

The two strands are parallel to each other

Question 4

A double-stranded DNA molecule contains 17% cytosine. What percentage of adenine would you expect to find?

Accepted Answer

33%

Question 5

Which analytical technique is most appropriate for determining the purity and concentration of a DNA sample?

Accepted Answer

Absorption of UV light at 260 nm

Question 6

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

Accepted Answer

A nucleotide contains a nitrogenous base, a pentose sugar, and a phosphate group

Question 7

Which of the following viruses uses RNA as its genetic material and requires reverse transcriptase for replication?

Accepted Answer

HIV

Question 8

Why is the GC content of a DNA molecule important in PCR (polymerase chain reaction)?

Accepted Answer

GC content determines which PCR buffer should be used due to its effect on DNA stability

Question 9

Which of the following is a correct description of a phosphodiester bond in nucleic acids?

Accepted Answer

A bond between the phosphate group at the C-5' position of one nucleotide and the OH group at the C-3' position of another

Question 10

Which experimental result provided the first direct evidence that DNA, not protein, is the genetic material in eukaryotes?

Accepted Answer

Recombinant DNA technology showing eukaryotic genes can be expressed in bacteria

Question 11

Which of the following best explains why nucleic acids absorb UV light strongly at 254–260 nm?

Accepted Answer

The interaction between UV light and the ring systems of the nitrogenous bases

Question 12

Which of the following statements about RNA is FALSE?

Accepted Answer

RNA contains the sugar deoxyribose

Question 13

Which of the following is a pyrimidine base found in both DNA and RNA?

Accepted Answer

Cytosine

Question 14

A scientist is using fluorescent in situ hybridization (FISH) to detect a specific DNA sequence in human chromosomes. What is the main principle behind this technique?

Accepted Answer

Hybridization of fluorescently labeled probes to complementary DNA sequences

Question 15

Which of the following best describes the role of triphosphates (e.g., ATP, GTP) in nucleic acid synthesis?

Accepted Answer

They serve as precursor molecules for nucleic acid synthesis, providing energy for bond formation

Question 16

Which of the following statements about the directionality of DNA synthesis is correct?

Accepted Answer

DNA is synthesized by extending the 3' end of the primer

Question 17

Which of the following is a direct result of the complementary base pairing in DNA?

Accepted Answer

A-T and G-C base pairs provide chemical stability to the helix

Question 18

Which of the following is a left-handed double helix form of DNA?

Accepted Answer

Z-DNA

Question 19

Which of the following best describes the outcome of Griffith's experiment with Streptococcus pneumoniae?

Accepted Answer

Living avirulent bacteria transformed into virulent bacteria when mixed with heat-killed virulent bacteria

Question 20

Which of the following is NOT a class of cellular RNA involved in gene expression?

Accepted Answer

Small interfering RNA (siRNA)

DNA Structure and Analysis: Foundations of Genetic Material

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