Question 1

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

Accepted Answer

Hershey & Chase's bacteriophage experiment

Question 2

A scientist mutates the gene encoding DNA ligase in a eukaryotic cell. Which process will be most directly affected?

Accepted Answer

Joining of Okazaki fragments on the lagging strand

Question 3

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

Accepted Answer

DNA is synthesized in the 5'→3' direction

Question 4

A mutation in the gene for telomerase would most likely affect which type of cells?

Accepted Answer

Germ cells and stem cells

Question 5

Which of the following statements about the lac operon is correct?

Accepted Answer

It is an inducible operon that is usually OFF

Question 6

Which enzyme is responsible for relieving the twisting tension ahead of the replication fork during DNA replication?

Accepted Answer

Topoisomerase

Question 7

A point mutation changes a codon from UAU to UAA. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 8

Which of the following best explains why alternative splicing increases protein diversity?

Accepted Answer

It enables a single gene to produce multiple mRNA variants

Question 9

Which of the following modifications would most likely result in increased gene expression?

Accepted Answer

Histone acetylation

Question 10

During translation, which site on the ribosome does the incoming aminoacyl-tRNA first bind?

Accepted Answer

A site

Question 11

A researcher observes that a certain mRNA is rapidly degraded and not translated. Which regulatory RNA is most likely involved?

Accepted Answer

miRNA

Question 12

Which of the following is a correct pairing of purines and pyrimidines in DNA?

Accepted Answer

Adenine pairs with thymine

Question 13

Which process requires a primer to begin synthesis?

Accepted Answer

DNA replication

Question 14

A mutation causes the loss of function of the spliceosome. What is the most likely consequence?

Accepted Answer

Failure to remove introns from pre-mRNA

Question 15

Which of the following best describes the role of the CRISPR-Cas9 system in gene editing?

Accepted Answer

It cuts DNA at specific sequences guided by RNA

Question 16

Which of the following is a direct result of a frameshift mutation?

Accepted Answer

The reading frame of the gene is altered

Question 17

Which of the following is true regarding the direction in which RNA polymerase synthesizes RNA?

Accepted Answer

RNA is synthesized in the 5'→3' direction

Question 18

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

Accepted Answer

Each new DNA molecule contains one old and one new strand

Question 19

Which of the following is a function of the proteasome in eukaryotic cells?

Accepted Answer

Degrading proteins tagged with ubiquitin

Question 20

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

Accepted Answer

Nucleotide excision repair

DNA Structure, Replication, Transcription, Translation, and Gene Regulation

Study Guide - Practice Questions