Question 1

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

Accepted Answer

Hershey and Chase's experiment using bacteriophages labeled with $$^{32}P$$ and $$^{35}S$$

Question 2

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 3

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

Accepted Answer

Topoisomerase

Question 4

In the Meselson-Stahl experiment, what result would you expect after two rounds of DNA replication in $$^{14}N$$ medium if DNA replication were dispersive?

Accepted Answer

One band at intermediate density

Question 5

Which of the following best describes the direction in which DNA polymerase synthesizes new DNA?

Accepted Answer

5' to 3' direction only

Question 6

A mutation occurs that disables the function of DNA ligase in a cell. Which process would be most directly affected?

Accepted Answer

Joining of Okazaki fragments on the lagging strand

Question 7

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

Accepted Answer

The sugar-phosphate backbone runs antiparallel, with one strand 5' to 3' and the other 3' to 5'

Question 8

Which enzyme is responsible for synthesizing short RNA primers during DNA replication?

Accepted Answer

Primase

Question 9

A scientist observes that a bacterial cell has a mutation in the gene encoding single-strand binding proteins. What is the most likely consequence during DNA replication?

Accepted Answer

The DNA strands will re-anneal before replication can proceed

Question 10

Which of the following best explains why mutations are important for evolution?

Accepted Answer

They provide genetic variation upon which natural selection can act

Question 11

In eukaryotic cells, what is the first level of DNA packing in chromatin?

Accepted Answer

Formation of nucleosomes by wrapping DNA around histones

Question 12

Which of the following is a direct result of the antiparallel structure of DNA during replication?

Accepted Answer

The lagging strand is synthesized discontinuously as Okazaki fragments

Question 13

Which process is responsible for correcting errors that escape proofreading during DNA replication?

Accepted Answer

Mismatch repair

Question 14

A patient is exposed to UV light, which causes thymine dimers in their DNA. Which DNA repair mechanism is most likely to fix this damage?

Accepted Answer

Nucleotide excision repair

Question 15

Which of the following best describes the role of dATP in DNA replication?

Accepted Answer

It provides adenine for the growing DNA strand and has deoxyribose as its sugar

Question 16

Which of the following is NOT a function of DNA polymerase I in prokaryotic DNA replication?

Accepted Answer

Joining Okazaki fragments together

Question 17

Which of the following statements about bacterial chromosomes is correct?

Accepted Answer

They are double-stranded, circular DNA molecules found in the nucleoid

Question 18

During DNA replication, which enzyme is responsible for unwinding the parental double helix at the replication fork?

Accepted Answer

Helicase

Question 19

Which of the following best explains why DNA replication is described as 'semiconservative'?

Accepted Answer

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

Question 20

Which of the following is a real-world consequence of mutations that are not repaired during DNA replication?

Accepted Answer

They can lead to genetic diseases or contribute to the evolution of new species

CH 16- The Molecular Basis of Inheritance: Structure and Replication of DNA

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