Question 1

Which of the following best describes the function of release factors during translation termination in prokaryotes?

Accepted Answer

They recognize stop codons and modify the ribosome to activate ribozymes, leading to dissociation of the ribosome.

Question 2

A mutation changes a single base pair in a gene, resulting in a different amino acid being incorporated into the protein. What type of mutation is this?

Accepted Answer

Missense mutation

Question 3

Which of the following statements about operons is correct?

Accepted Answer

An operon is a series of genes controlled by a regulatory element called an operator.

Question 4

The lac operon is an example of an inducible operon. Under which condition is the lac operon most likely to be transcribed?

Accepted Answer

When lactose is present and glucose is absent.

Question 5

Which of the following best explains why some genes are only transcribed and translated when needed?

Accepted Answer

To conserve cellular energy and resources.

Question 6

A frameshift mutation is most likely to result from which of the following events?

Accepted Answer

Insertion or deletion of nucleotides not in multiples of three.

Question 7

Which repair mechanism is considered the 'last resort' for cells with extensive DNA damage?

Accepted Answer

Error-prone repair (SOS response)

Question 8

Which of the following is a correct statement about the trp operon?

Accepted Answer

It is a repressible operon that is deactivated by the presence of tryptophan.

Question 9

A student exposes bacteria to ultraviolet light and observes the formation of thymine dimers. What type of mutagen is ultraviolet light?

Accepted Answer

Nonionizing radiation

Question 10

Which of the following best describes the role of CAP-cAMP in the regulation of the lac operon?

Accepted Answer

CAP-cAMP enhances transcription by facilitating RNA polymerase binding to the promoter.

Question 11

Which of the following is a consequence of a nucleotide analog being incorporated into DNA during replication?

Accepted Answer

It can disrupt DNA and RNA replication, leading to base-pair substitutions and missense mutations.

Question 12

Which method is commonly used to identify mutants that have gained resistance to an antibiotic?

Accepted Answer

Positive selection

Question 13

What is the primary difference between generalized and specialized transduction in bacteria?

Accepted Answer

Generalized transduction transfers random DNA segments, while specialized transduction transfers specific donor DNA sequences.

Question 14

Which of the following best describes a transposon?

Accepted Answer

A segment of DNA that can move from one location to another, causing frameshift insertions.

Question 15

A researcher uses the Ames test to evaluate a chemical's mutagenic potential. What is the principle behind the Ames test?

Accepted Answer

It detects the ability of a chemical to induce mutations that restore function to a mutant gene.

Question 16

Which of the following horizontal gene transfer mechanisms requires the recipient cell to be competent?

Accepted Answer

Transformation

Question 17

If a cell fails to repair a mutation, what is the term for its descendants?

Accepted Answer

Mutants

Question 18

Which of the following equations best represents the increase in mutation rate due to mutagens?

Accepted Answer

$$	ext{Mutation Rate}_{	ext{mutagen}} = (10 	ext{ to } 1000) 	imes 	ext{Mutation Rate}_{	ext{spontaneous}}$$

Question 19

Which of the following is NOT a typical method for repairing damaged DNA in cells?

Accepted Answer

Frameshift repair

Question 20

A bacterial cell receives a segment of DNA from another cell via a bacteriophage. What is this process called?

Accepted Answer

Transduction

Microbial Genetics: Regulation of Genetic Expression and Operons

Study Guide - Practice Questions

Study Guide - Flashcards