Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A mutation that results in the insertion of a single nucleotide into a gene sequence is most likely to cause which of the following?

Accepted Answer

A frameshift mutation

Question 3

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 4

In the lac operon of E. coli, what happens when lactose is present?

Accepted Answer

The repressor is inactivated by an inducer, allowing transcription.

Question 5

Which of the following best explains why mutations are important for evolution?

Accepted Answer

Mutations create genetic diversity, which is the raw material for natural selection.

Question 6

Which of the following is a function of plasmids in bacteria?

Accepted Answer

They may carry genes for antibiotic resistance and toxin production.

Question 7

A missense mutation results in:

Accepted Answer

A change in the amino acid sequence of the protein.

Question 8

Which of the following statements about bacterial DNA replication is correct?

Accepted Answer

Replication is bidirectional and each daughter cell receives one copy of the DNA molecule.

Question 9

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

Accepted Answer

It transports amino acids to the ribosome and matches them to the mRNA codon.

Question 10

Which of the following is true regarding the regulation of gene expression in bacteria?

Accepted Answer

Inducible operons are usually off but can be turned on by an inducer.

Question 11

A scientist exposes bacteria to a chemical and observes an increased rate of mutation. This chemical is best described as a:

Accepted Answer

Mutagen

Question 12

Which of the following is a key difference between generalized and specialized transduction in bacteria?

Accepted Answer

Generalized transduction can transfer any bacterial gene, while specialized transduction transfers only specific genes.

Question 13

Which of the following best describes the role of the operator in an operon?

Accepted Answer

It is the site where the repressor protein binds to regulate transcription.

Question 14

A bacterial cell is exposed to UV radiation, resulting in the formation of thymine dimers. Which repair mechanism can directly reverse this damage?

Accepted Answer

Photolyase-mediated light repair

Question 15

In the Ames test, why is rat liver extract added to the assay?

Accepted Answer

To supply activation enzymes that may convert chemicals into mutagens

Question 16

Which of the following is an example of horizontal gene transfer in bacteria?

Accepted Answer

A bacterium acquiring DNA from a virus (bacteriophage)

Question 17

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are joined together by DNA ligase to form a continuous DNA strand.

Question 18

A bacterial cell with an F factor integrated into its chromosome is called:

Accepted Answer

Hfr cell

Question 19

Which of the following best describes a silent mutation?

Accepted Answer

A mutation that does not change the amino acid sequence of the protein

Question 20

Which of the following is true about the genetic code?

Accepted Answer

There are 64 possible codons, but only 20 amino acids.

Microbial Genetics: Structure, Function, and Mechanisms

Study Guide - Practice Questions