Question 1

Which experiment provided definitive evidence that DNA, and not protein, is the genetic material in cells?

Accepted Answer

The Hershey-Chase experiment using radioactive isotopes

Question 2

In the Hershey-Chase experiment, which radioactive isotope was used to label DNA?

Accepted Answer

$$^{32}\mathrm{P}$$

Question 3

Which of the following best describes the structure of DNA as determined by Watson and Crick?

Accepted Answer

A double helix with antiparallel strands and complementary base pairing

Question 4

According to Chargaff’s rules, if a DNA sample contains 22% adenine, what percentage of thymine should it contain?

Accepted Answer

22%

Question 5

Which enzyme is responsible for relieving the tension caused by unwinding of the DNA double helix during replication?

Accepted Answer

Topoisomerase

Question 6

What is the role of single-stranded binding proteins (SSBPs) during DNA replication?

Accepted Answer

They prevent the separated DNA strands from re-annealing

Question 7

Which of the following statements about the leading and lagging strands during DNA replication is correct?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized in Okazaki fragments

Question 8

Why do eukaryotic chromosomes not become progressively shorter with each round of DNA replication?

Accepted Answer

Telomerase extends the telomeres at the ends of chromosomes

Question 9

Which of the following best explains why the actual error rate of DNA replication is much lower than the theoretical rate?

Accepted Answer

DNA polymerase proofreading and mismatch repair mechanisms

Question 10

A mutation in which enzyme would most likely result in the inability to join Okazaki fragments on the lagging strand?

Accepted Answer

DNA ligase

Question 11

Which of the following is a purine base found in DNA?

Accepted Answer

Adenine

Question 12

What is the function of primase during DNA replication?

Accepted Answer

It synthesizes a short RNA primer to provide a starting point for DNA polymerase

Question 13

Which feature of DNA structure allows for the accurate copying of genetic information during replication?

Accepted Answer

Complementary base pairing

Question 14

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand

Question 15

Which of the following is NOT a function of DNA polymerase during replication?

Accepted Answer

Unwinding the DNA double helix

Question 16

Which of the following best explains why prokaryotic chromosomes typically have a single origin of replication, while eukaryotic chromosomes have multiple origins?

Accepted Answer

Eukaryotic chromosomes are much larger and linear, requiring multiple origins for efficient replication

Question 17

Which of the following is a direct consequence of telomere shortening in somatic cells?

Accepted Answer

Cellular aging and eventual cessation of cell division

Question 18

Which of the following best describes the role of nucleosomes in eukaryotic cells?

Accepted Answer

They help compact DNA so it fits within the nucleus

Question 19

Which of the following is a real-world application of understanding DNA replication mechanisms?

Accepted Answer

Developing targeted cancer therapies that inhibit telomerase in tumor cells

Question 20

Which of the following equations correctly represents the relationship between the percentages of bases in double-stranded DNA according to Chargaff’s rules?

Accepted Answer

$$[A] = [T]$$ and $$[G] = [C]$$

DNA Structure and Replication: Foundations of Genetic Material

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