Question 1

Which of the following experiments provided the most direct evidence that DNA, and not protein, is the hereditary material in bacteriophages?

Accepted Answer

Hershey and Chase's radioactive labeling of phage DNA and protein

Question 2

Which property of DNA best explains its ability to serve as a template for its own replication?

Accepted Answer

Its double helix structure with antiparallel strands

Question 3

A DNA molecule is analyzed and found to have 30% adenine. According to base pairing rules, what percentage of guanine would you expect?

Accepted Answer

$$20\%$$

Question 4

Which of the following best describes the chemical bond formed between adjacent nucleotides in a single DNA strand?

Accepted Answer

Phosphodiester bond between the 3' hydroxyl and 5' phosphate

Question 5

In the Meselson-Stahl experiment, after two rounds of replication in $$^{14}N$$ medium, what proportion of DNA molecules would have only $$^{14}N$$?

Accepted Answer

Half the molecules

Question 6

Which feature of DNA allows for the formation of major and minor grooves?

Accepted Answer

Base stacking and the helical twist of the double helix

Question 7

Which of the following statements about Z-form DNA is correct?

Accepted Answer

It is commonly found near transcription start sites

Question 8

A scientist treats a mixture of heat-killed SIII and live RII Pneumococcus with an enzyme that destroys RNA. What is the expected outcome when this mixture is injected into mice?

Accepted Answer

Mice die; live SIII bacteria are recovered

Question 9

Which of the following best explains why proteins were initially considered as candidates for the hereditary material instead of DNA?

Accepted Answer

Proteins are more chemically complex than DNA

Question 10

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

Accepted Answer

Formation of stable hydrogen bonds between complementary bases

Question 11

Which experimental result would support the conservative model of DNA replication?

Accepted Answer

After one round of replication, two distinct bands corresponding to parental and daughter DNA are observed

Question 12

Which of the following best describes the difference between dNMPs and dNTPs?

Accepted Answer

dNMPs are incorporated into DNA chains; dNTPs are free nucleotides with three phosphates

Question 13

Which of the following is NOT an essential characteristic of hereditary material as identified before DNA was known to be the hereditary molecule?

Accepted Answer

It must be able to catalyze metabolic reactions

Question 14

Which of the following best explains why the diameter of B-form DNA is constant along its length?

Accepted Answer

Each base pair consists of one purine and one pyrimidine

Question 15

Which of the following is a real-world application of the concept of DNA's mutability?

Accepted Answer

The development of antibiotic resistance in bacteria

Question 16

Which of the following statements about the directionality of DNA replication in eukaryotes is correct?

Accepted Answer

Replication initiates at multiple origins and proceeds bidirectionally

Question 17

Which enzyme catalyzes the formation of the phosphodiester bond during DNA strand elongation?

Accepted Answer

DNA polymerase

Question 18

Which of the following best describes the outcome of Griffith's experiment when mice were injected with heat-killed SIII and live RII bacteria?

Accepted Answer

Mice died and live SIII bacteria were recovered

Question 19

Which of the following is a direct result of base stacking in the DNA double helix?

Accepted Answer

The helical twist of the DNA molecule

DNA Structure and Replication: Foundations of Genetic Inheritance

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