Question 1

Which of the following experiments provided the first strong evidence that DNA, and not protein, is the genetic material responsible for heredity?

Accepted Answer

Avery, Macleod, and McCarty’s enzymatic elimination experiments

Question 2

In the Hershey-Chase experiment, which radioactive label was found inside the bacterial cells after infection by bacteriophage, indicating the genetic material?

Accepted Answer

Radioactive phosphorus ($$^{32}P)$$

Question 3

Which of the following best describes Chargaff’s rules?

Accepted Answer

The amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine

Question 4

A nucleotide is composed of which three components?

Accepted Answer

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

Question 5

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

Accepted Answer

The two strands are antiparallel and held together by hydrogen bonds between complementary bases

Question 6

Which scientist’s work directly demonstrated that the ‘transforming principle’ was DNA by using enzymes to selectively destroy macromolecules?

Accepted Answer

Oswald Avery

Question 7

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

Accepted Answer

$$20\%$$

Question 8

Which of the following is NOT a requirement for a molecule to serve as the genetic material?

Accepted Answer

It must be able to catalyze metabolic reactions

Question 9

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

Accepted Answer

Proteins have greater structural complexity due to 20 different amino acids

Question 10

A mutation in a gene alters the sequence of DNA. According to the central dogma, what is the most likely consequence?

Accepted Answer

A change in the sequence of RNA and possibly the protein product

Question 11

Which of the following is a real-world application of bacteriophage, as discussed in the study materials?

Accepted Answer

Treatment of antibiotic-resistant bacterial infections

Question 12

Which chemical element is present in DNA but not in most proteins, and was used in the Hershey-Chase experiment to label DNA?

Accepted Answer

Phosphorus

Question 13

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

Accepted Answer

A nucleoside contains a sugar and a base; a nucleotide contains a sugar, a base, and a phosphate group

Question 14

Which historical period saw the characterization of the central dogma of molecular biology?

Accepted Answer

1953–2003

Question 15

Which of the following is the correct sequence of information flow according to the central dogma?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 16

Which of the following best describes the role of Rosalind Franklin in the discovery of DNA structure?

Accepted Answer

She performed X-ray crystallography that revealed the helical structure of DNA

Question 17

Which of the following is a property of the sugar found in DNA nucleotides?

Accepted Answer

It is a pentose with a hydrogen at the 2’ carbon

Question 18

A scientist treats a bacterial cell extract with protease, RNase, and DNase. Only when DNase is added does transformation fail to occur. What does this indicate?

Accepted Answer

DNA is required for transformation

Question 19

Which of the following is a direct consequence of the antiparallel nature of DNA strands?

Accepted Answer

The 5’ end of one strand aligns with the 3’ end of the other

Question 20

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

Accepted Answer

DNA is more chemically stable due to the absence of a 2’ hydroxyl group

DNA as the Genetic Material: Historical Experiments and Molecular Structure

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