Question 1

Which of the following best describes the four essential criteria that genetic material must fulfill, as established by molecular genetics?

Accepted Answer

It must contain information, be transmissible, be capable of replication, and allow for variation.

Question 2

In the classic Griffith transformation experiment, which combination of bacterial strains and treatments resulted in the death of the mice, demonstrating the concept of transformation?

Accepted Answer

Injection of a mixture of live type IIR and heat-killed type IIIS bacteria.

Question 3

Which experimental evidence from the Hershey-Chase experiment conclusively demonstrated that DNA, and not protein, is the genetic material in bacteriophages?

Accepted Answer

Radioactive phosphorus was found inside the bacterial cells after infection.

Question 4

Which of the following correctly matches the chemical structure of a nucleotide found in DNA?

Accepted Answer

Nitrogenous base + deoxyribose + phosphate group

Question 5

Which of the following statements about the structure of the DNA double helix is CORRECT?

Accepted Answer

The two strands are antiparallel and stabilized by hydrogen bonds and base stacking.

Question 6

According to Chargaff’s rules, if a DNA sample contains 30% adenine, what percentage of guanine would you expect to find?

Accepted Answer

$$20\%$$

Question 7

Which of the following best explains why only about 1.5% of the human genome codes for proteins?

Accepted Answer

The majority of the genome consists of introns, regulatory sequences, and non-coding DNA.

Question 8

Which of the following is a unique feature of Z-DNA compared to B-DNA?

Accepted Answer

Z-DNA is left-handed and has 12 base pairs per turn.

Question 9

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 10

Which of the following is a real-world application of triplex DNA formation?

Accepted Answer

Triplex DNA can be used as a tool for therapeutic gene inactivation.

Question 11

Which of the following statements about RNA structure is CORRECT?

Accepted Answer

RNA contains uracil instead of thymine and ribose instead of deoxyribose.

Question 12

Which of the following best explains the significance of Rosalind Franklin’s X-ray diffraction data in the discovery of DNA structure?

Accepted Answer

It provided evidence for the helical structure and regular spacing of base pairs in DNA.

Question 13

Which of the following sequences would most likely favor the formation of Z-DNA under high salt conditions?

Accepted Answer

$$	ext{GCGCGCGCGC}$$

Question 14

Which of the following is a correct description of the directionality of a DNA strand?

Accepted Answer

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

Question 15

Which of the following best explains why the polysaccharide coat of the S strain of Streptococcus pneumoniae is important in Griffith’s experiment?

Accepted Answer

It inhibits the host’s immune system, making the bacteria virulent.

Question 16

Which of the following is a plausible explanation for the presence of 223 genes in humans that match those in bacteria but are not found in intermediate organisms?

Accepted Answer

These genes may have been transferred horizontally between bacteria and humans.

Question 17

Which of the following best describes the role of hydrogen bonds in the DNA double helix?

Accepted Answer

Hydrogen bonds stabilize the pairing between complementary bases.

Question 18

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

Accepted Answer

Both grooves allow proteins to interact with specific base sequences.

Question 19

Which of the following best explains why DNA is considered acidic?

Accepted Answer

Because the phosphate groups in the backbone can release protons ($$	ext{H}^+) in $$solution.

Question 20

Which of the following is a real-world implication of the fact that the human genome contains only about 1.5% protein-coding DNA?

Accepted Answer

Regulatory and non-coding regions play significant roles in gene expression and genome evolution.

Ch 9: Molecular Structure of DNA and RNA: Foundations of Genetic Material

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