Question 1

Which of the following best describes the antiparallel nature of DNA strands?

Accepted Answer

One DNA strand runs 5' to 3', while the other runs 3' to 5'.

Question 2

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

Accepted Answer

Helicase

Question 3

Which of the following base pairs is stabilized by three hydrogen bonds?

Accepted Answer

Guanine-Cytosine

Question 4

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

Accepted Answer

Nonsense mutation

Question 5

Which process involves the uptake of naked DNA from the environment by a bacterial cell?

Accepted Answer

Transformation

Question 6

What is the role of the RNA primer during DNA replication?

Accepted Answer

It provides a starting point for DNA polymerase to add nucleotides.

Question 7

Which of the following is true about the genetic code?

Accepted Answer

There are 64 possible codons and 20 amino acids.

Question 8

In the lac operon, what happens when lactose is present and glucose is absent?

Accepted Answer

The lac operon is highly transcribed due to the presence of allolactose and high cAMP.

Question 9

Which of the following best describes a frameshift mutation?

Accepted Answer

One or more nucleotides are inserted or deleted, altering the reading frame.

Question 10

Which enzyme is responsible for synthesizing RNA during transcription?

Accepted Answer

RNA polymerase

Question 11

What is the function of the poly-A tail added to eukaryotic mRNA?

Accepted Answer

It protects mRNA from degradation and aids in export from the nucleus.

Question 12

Which of the following is a function of topoisomerase during DNA replication?

Accepted Answer

It relieves overwinding strain ahead of the replication fork.

Question 13

A bacterial cell receives DNA from a bacteriophage. This process is called:

Accepted Answer

Transduction

Question 14

Which of the following statements about tRNA is correct?

Accepted Answer

tRNA brings amino acids to the ribosome during translation.

Question 15

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

Accepted Answer

Eukaryotes use a TATA box and transcription factors, while prokaryotes use a Pribnow box.

Question 16

Which of the following best explains why the lac operon is considered an inducible operon?

Accepted Answer

It is turned on only in the presence of lactose.

Question 17

Which of the following is a consequence of alternative RNA splicing?

Accepted Answer

It allows a single gene to code for multiple proteins.

Question 18

Which of the following is true about transposons?

Accepted Answer

They can move genes, such as antibiotic resistance, between plasmids.

Question 19

A bacterial cell with an integrated F plasmid that can transfer chromosomal genes during conjugation is called:

Accepted Answer

Hfr cell

Question 20

Which of the following best describes a repressible operon?

Accepted Answer

It is usually on but can be inhibited when a specific molecule is present.

Microbial Genetics: Structure, Replication, Expression, and Regulation

Study Guide - Practice Questions