Question 1

Which of the following best describes semiconservative DNA replication, as demonstrated by the Meselson-Stahl experiment?

Accepted Answer

Each daughter DNA molecule contains one strand from the parent and one newly synthesized strand.

Question 2

During DNA replication, which enzyme is primarily responsible for relieving supercoiling ahead of the replication fork?

Accepted Answer

Topoisomerase

Question 3

A patient is found to have a mutation that prevents the formation of Okazaki fragments. Which strand of DNA synthesis is most directly affected?

Accepted Answer

Lagging strand

Question 4

Which of the following best explains the end-replication problem in eukaryotic cells?

Accepted Answer

DNA polymerases cannot fully replicate the 3' ends of linear chromosomes, leading to progressive shortening.

Question 5

A cell is exposed to UV radiation, resulting in thymine dimers. Which DNA repair pathway is most likely to fix this damage?

Accepted Answer

Nucleotide excision repair

Question 6

Which of the following statements about translesion DNA synthesis is correct?

Accepted Answer

It allows DNA replication to continue past damaged sites but is error-prone due to lack of proofreading.

Question 7

Which protein complex is essential for the initiation of DNA replication in eukaryotes by loading the helicase onto DNA?

Accepted Answer

MCM complex

Question 8

A mutation in the gene encoding Rad51 would most directly impair which DNA repair process?

Accepted Answer

Homologous recombination repair of double-strand breaks

Question 9

Which of the following is a key difference between prokaryotic and eukaryotic transcription?

Accepted Answer

Prokaryotes use a single RNA polymerase, while eukaryotes use multiple distinct RNA polymerases.

Question 10

Which sequence is recognized by the sigma factor during bacterial transcription initiation?

Accepted Answer

Promoter sequence

Question 11

Which of the following best describes the function of the TATA box in eukaryotic transcription?

Accepted Answer

It serves as a core promoter element where transcription factors and RNA polymerase assemble.

Question 12

Which RNA molecule is directly involved in catalyzing the splicing of pre-mRNA in eukaryotes?

Accepted Answer

snRNA

Question 13

Which of the following statements about the central dogma of molecular biology is correct?

Accepted Answer

It describes the flow of genetic information as DNA $$\rightarrow$$ RNA $$\rightarrow$$ protein.

Question 14

Which of the following is a property of the genetic code that helps explain why sickle cell anemia is caused by a single nucleotide change?

Accepted Answer

The code is a triplet code, so a single base change can alter one amino acid.

Question 15

A frameshift mutation is most likely to occur due to which of the following?

Accepted Answer

Insertion or deletion of a nucleotide not in multiples of three

Question 16

Which site on the ribosome is responsible for accepting incoming aminoacyl-tRNAs during translation?

Accepted Answer

A site

Question 17

According to the wobble hypothesis, which position in the codon-anticodon pairing allows for non-standard base pairing?

Accepted Answer

The third position of the codon

Question 18

Which sequence is important for translation initiation in prokaryotes?

Accepted Answer

Shine-Dalgarno sequence

Question 19

A patient with a mutation in the gene encoding GroEL would most likely have defects in which cellular process?

Accepted Answer

Protein folding

Question 20

Insulin is synthesized as a precursor molecule and then processed to its active form. This is an example of which cellular process?

Accepted Answer

Posttranslational modification

DNA Replication, Gene Expression, and Protein Synthesis: Study Guide for Chapters 17–19

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