Question 1

Which experiment provided the strongest evidence that DNA replication is semi-conservative, and what does 'semi-conservative' mean in this context?

Accepted Answer

Meselson-Stahl experiment; each new DNA molecule contains one old and one new strand

Question 2

During DNA replication, which enzyme is responsible for relieving supercoiling ahead of the replication fork, and what would happen if this enzyme were nonfunctional?

Accepted Answer

Topoisomerase; DNA replication would stall due to excessive supercoiling

Question 3

Which of the following best describes the directionality of new DNA strand synthesis during replication?

Accepted Answer

5' to 3' direction

Question 4

A mutation disables the proofreading function of DNA polymerase. What is the most likely consequence?

Accepted Answer

Increased rate of spontaneous mutations

Question 5

Which of the following statements about the lagging strand during DNA replication is correct?

Accepted Answer

It is synthesized discontinuously in short fragments called Okazaki fragments

Question 6

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

Accepted Answer

They prevent separated DNA strands from reannealing

Question 7

Which of the following best explains why telomeres shorten with each round of DNA replication in most somatic cells?

Accepted Answer

DNA polymerase cannot fully replicate the ends of linear chromosomes

Question 8

Which enzyme is responsible for replacing RNA primers with DNA nucleotides during DNA replication in prokaryotes?

Accepted Answer

DNA polymerase I

Question 9

A scientist observes that a cell can no longer add a 5' cap or poly-A tail to its mRNA. What is the most likely consequence?

Accepted Answer

The mRNA will be rapidly degraded and translation efficiency will decrease

Question 10

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome based on codon-anticodon pairing

Question 11

Which of the following is true regarding the central dogma of molecular biology?

Accepted Answer

Information flows from DNA to RNA to protein

Question 12

A mutation in the promoter region of a gene would most likely affect which process?

Accepted Answer

The initiation of transcription

Question 13

Which of the following post-translational modifications is most likely to target a protein for degradation?

Accepted Answer

Ubiquitination

Question 14

If a eukaryotic cell lacked functional spliceosomes, what would be the most direct effect on gene expression?

Accepted Answer

Pre-mRNA would retain introns and produce nonfunctional proteins

Question 15

Which of the following best explains why multiple ribosomes can translate a single mRNA molecule simultaneously?

Accepted Answer

Ribosomes can bind to the mRNA at different points, forming a polysome

Question 16

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

Accepted Answer

Eukaryotes process pre-mRNA before translation

Question 17

A DNA sequence has the following coding strand: 5'-ATG GGC TAA-3'. What is the corresponding mRNA sequence?

Accepted Answer

5'-AUG GGC UAA-3'

Question 18

Which of the following best describes the role of the ribosome during translation?

Accepted Answer

It catalyzes the formation of peptide bonds between amino acids

Question 19

Which of the following is a function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

It protects mRNA from degradation and assists in ribosome binding

Molecular Basis of Inheritance and Gene Expression: DNA Replication, Repair, and Protein Synthesis

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