Question 1

Which experiment provided evidence that DNA is the genetic material, and what was the key finding?

Accepted Answer

Hershey and Chase; they demonstrated that DNA, not protein, is injected by viruses into bacteria.

Question 2

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides to the 3' end?

Accepted Answer

DNA polymerase

Question 3

A mutation changes a codon from UAU to UAA. What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

Nonsense mutation; results in a premature stop codon.

Question 4

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

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the coded mRNA message.

Question 5

In the regulation of the lac operon in E. coli, what happens when lactose is present and glucose is absent?

Accepted Answer

The operon is transcribed at high levels because the repressor is inactive and CAP is bound.

Question 6

Which process is responsible for the removal of introns from pre-mRNA in eukaryotic cells?

Accepted Answer

Splicing

Question 7

A scientist uses PCR to amplify a segment of DNA. Which enzyme is essential for this process, and why?

Accepted Answer

Taq polymerase; it synthesizes new DNA strands at high temperatures.

Question 8

Which of the following best explains why mutations in somatic cells do not get passed to offspring?

Accepted Answer

Somatic cells do not undergo meiosis to form gametes.

Question 9

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

Accepted Answer

Transcription and translation are coupled in prokaryotes but separated in eukaryotes.

Question 10

A patient is diagnosed with a genetic disorder caused by a single nucleotide substitution. Which type of mutation is most likely responsible?

Accepted Answer

Point mutation

Question 11

Which of the following best describes the Meselson-Stahl experiment's conclusion about DNA replication?

Accepted Answer

DNA replication is semiconservative.

Question 12

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 13

A researcher is studying gene expression in eukaryotes. Which process allows a single gene to code for multiple proteins?

Accepted Answer

Alternative splicing

Question 14

Which of the following is a function of the CRISPR-Cas9 system in biotechnology?

Accepted Answer

Editing specific genes within an organism's genome

Question 15

Which of the following best describes a promoter in gene regulation?

Accepted Answer

A DNA sequence where RNA polymerase binds to initiate transcription

Question 16

A mutation in the gene encoding the repressor protein of the lac operon prevents it from binding to the operator. What is the likely outcome?

Accepted Answer

The operon will be constitutively expressed.

Question 17

Which of the following best explains why eukaryotic cells can regulate gene expression at multiple levels?

Accepted Answer

Eukaryotic gene expression involves chromatin remodeling, transcription, RNA processing, and translation.

Question 18

Which of the following is a real-world application of DNA fingerprinting?

Accepted Answer

Identifying individuals in forensic investigations

Question 19

Which of the following best describes the role of RNA primers in DNA replication?

Accepted Answer

They provide a starting point for DNA polymerase to begin synthesis.

Question 20

A patient has a mutation that affects the function of their ribosomes. Which cellular process is most directly impacted?

Accepted Answer

Translation

BIOL 190A 1001 Final Study Guide: Molecular Genetics, Gene Expression, and Evolution

Study Guide - Practice Questions