Question 1

Which of the following best describes the difference between sterilization and disinfection?

Accepted Answer

Sterilization destroys all forms of microbial life, including spores, while disinfection eliminates most pathogenic organisms but not necessarily spores.

Question 2

A hospital uses autoclaving to sterilize surgical instruments. Which method of microbial control is this an example of?

Accepted Answer

Physical agent

Question 3

Which phase of the microbial death curve is characterized by a constant rate of cell death, and can be mathematically described by the following equation: $N_t = N_0 e^{-kt}$, where $N_t$ is the number of surviving cells at time $t$, $N_0$ is the initial number of cells, and $k$ is the death rate constant?

Accepted Answer

Exponential death phase

Question 4

Which of the following terms refers to the process by which genetic information is transferred from DNA to RNA?

Accepted Answer

Transcription

Question 5

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 6

A mutation that changes a codon from coding for an amino acid to a stop codon is called:

Accepted Answer

Nonsense mutation

Question 7

Which of the following is NOT a base substitution mutation?

Accepted Answer

Frameshift mutation

Question 8

In the lac operon, which molecule acts as the inducer to initiate transcription of the structural genes?

Accepted Answer

Lactose

Question 9

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

Accepted Answer

Brings amino acids to the ribosome and matches them to the coded mRNA message

Question 10

A researcher exposes bacteria to UV radiation, resulting in the formation of thymine dimers. What type of mutation is most likely to occur?

Accepted Answer

Radiation-induced mutation

Question 11

Which of the following is a real-world example of a mechanical agent used for microbial control?

Accepted Answer

Filtration of air in hospital operating rooms

Question 12

Which of the following statements about the three domains of life is correct?

Accepted Answer

Archaea are more closely related to Eukarya than to Bacteria.

Question 13

Gram staining is used to differentiate bacteria based on:

Accepted Answer

The thickness of the peptidoglycan layer in the cell wall

Question 14

Which of the following is NOT a characteristic used in Bergey's Manual of Determinative Bacteriology to classify bacteria?

Accepted Answer

Ability to photosynthesize

Question 15

A mutation in the operator region of an operon could result in:

Accepted Answer

Uncontrolled expression of structural genes

Question 16

Which of the following best describes the role of a co-repressor in gene regulation?

Accepted Answer

Binds to the repressor protein to enable it to block transcription

Question 17

Which of the following kingdoms contains organisms that are primarily multicellular, photosynthetic, and have cell walls made of cellulose?

Accepted Answer

Plantae

Question 18

A patient is diagnosed with a bacterial infection. The laboratory uses phage typing to identify the strain. What does phage typing rely on?

Accepted Answer

The susceptibility of bacteria to specific bacteriophages

Question 19

Which of the following statements about genetic recombination is correct?

Accepted Answer

It results in the exchange of genetic material between different DNA molecules.

Question 20

Which of the following is a correct description of an operon?

Accepted Answer

A group of genes regulated together, including a promoter, operator, and structural genes

Microbiology Study Guide: Key Concepts and Learning Objectives

Study Guide - Practice Questions

Study Guide - Flashcards