Question 1

Which of the following is NOT one of the four major characteristics required for a molecule to serve as genetic material?

Accepted Answer

Ability to form a double helix

Question 2

In the Hershey–Chase experiment, what was the main evidence that DNA, and not protein, is the genetic material?

Accepted Answer

Radioactive phosphorus was found inside the bacterial cells

Question 3

Which experimental result would have invalidated Avery, MacLeod, and McCarty’s conclusion that DNA is the transforming principle?

Accepted Answer

Transformation does not occur after treatment with DNase

Question 4

A sample of DNA is found to contain 19% guanine. According to Chargaff’s rules, what percentage of adenine would you expect in this DNA?

Accepted Answer

$$31\%$$

Question 5

Which of the following statements about purines and pyrimidines is correct?

Accepted Answer

Adenine and guanine are purines; cytosine, thymine, and uracil are pyrimidines.

Question 6

Which chemical group is present at the 2' carbon of ribose but absent in deoxyribose?

Accepted Answer

A hydroxyl group ($$-OH)$$

Question 7

What type of bond links two nucleotides together in a DNA strand?

Accepted Answer

Phosphodiester bond

Question 8

If a mutation causes a change in the chemical composition of DNA, which property of genetic material does this illustrate?

Accepted Answer

Variation by mutation

Question 9

Which of the following best explains why proteins were initially favored over DNA as the genetic material by many scientists in the early 20th century?

Accepted Answer

Proteins are more abundant and chemically diverse than DNA.

Question 10

Which of the following is a direct application of recombinant DNA technology?

Accepted Answer

Producing human insulin in bacteria

Question 11

Which of the following wavelengths is most effective at inducing mutations in DNA?

Accepted Answer

$$260\ \mathrm{nm}$$

Question 12

Which of the following best describes a nucleoside?

Accepted Answer

A nitrogenous base and a pentose sugar

Question 13

Which of the following is true regarding the base composition of DNA according to Chargaff’s rules?

Accepted Answer

$$[A] = [T]$$

Question 14

Which of the following would be the result if Hershey and Chase had used a phage that completely entered the cell (protein coat and all) instead of injecting only its DNA?

Accepted Answer

They would have been unable to distinguish whether DNA or protein was the genetic material.

Question 15

Which of the following is a pyrimidine found only in RNA?

Accepted Answer

Uracil

Question 16

Which of the following best describes the role of ATP and GTP in the cell?

Accepted Answer

They serve as precursor molecules during nucleic acid synthesis and are important in cell bioenergetics.

Question 17

Which of the following statements about phosphodiester bonds is correct?

Accepted Answer

They link the 5' phosphate group of one nucleotide to the 3' hydroxyl group of another.

Question 18

Which of the following best explains why DNA, and not protein, is considered the genetic material based on UV absorption studies?

Accepted Answer

DNA absorbs UV light at the same wavelength that is most mutagenic to cells.

Question 19

Which of the following is a correct statement about the chemical structure of DNA and RNA?

Accepted Answer

DNA contains thymine and deoxyribose.

DNA Structure and Analysis – Essentials of Genetics (Chapter 9, Part I)

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