Question 1

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

Accepted Answer

Sterilization removes all forms of microbial life, including spores, while disinfection eliminates only vegetative pathogens.

Question 2

A hospital is deciding between using dry heat and autoclaving to sterilize surgical instruments. Which of the following statements is correct regarding these physical methods of microbial control?

Accepted Answer

Autoclaving uses moist heat under pressure and is generally more effective and faster than dry heat sterilization.

Question 3

Which of the following best describes the microbial death curve?

Accepted Answer

It shows the logarithmic decline in the number of viable microbes over time when exposed to a microbial control agent.

Question 4

Which of the following terms refers to the process of transferring genetic material from one bacterium to another via a bacteriophage?

Accepted Answer

Transduction

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 changes a codon from $	ext{UAC}$ (tyrosine) to $	ext{UAA}$ (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 7

Which of the following best describes the function of an operon in prokaryotic gene regulation?

Accepted Answer

A cluster of genes under the control of a single promoter and operator, allowing coordinated expression.

Question 8

A researcher exposes bacteria to UV radiation, resulting in the formation of thymine dimers. What is the most likely effect on the bacterial DNA?

Accepted Answer

It causes mutations by distorting the DNA structure and interfering with replication.

Question 9

Which of the following is NOT a method used to classify microorganisms?

Accepted Answer

Measuring the gravitational pull of the cell

Question 10

A patient is diagnosed with a bacterial infection. The laboratory uses Gram staining to help identify the causative agent. What is the primary purpose of Gram staining?

Accepted Answer

To differentiate bacteria based on differences in their cell wall structure

Question 11

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

Accepted Answer

Archaea and Bacteria are both prokaryotic, but Archaea have unique membrane lipids and gene expression machinery.

Question 12

Which of the following best describes a missense mutation?

Accepted Answer

A base substitution that results in a different amino acid being incorporated into the protein.

Question 13

Which of the following is a function of tRNA during translation?

Accepted Answer

It brings the appropriate amino acid to the ribosome based on the codon sequence of mRNA.

Question 14

A bacterial operon is regulated by a repressor protein that binds to the operator in the absence of an inducer. Which type of operon is this?

Accepted Answer

Inducible operon

Question 15

Which of the following best explains why chemical agents such as phenol are used in microbial control?

Accepted Answer

They disrupt cell membranes and denature proteins, leading to cell death.

Question 16

A scientist is using Bergey's Manual of Determinative Bacteriology. What is the primary purpose of this manual?

Accepted Answer

To identify and classify bacteria based on their characteristics

Question 17

Which of the following is a real-world example of horizontal gene transfer in bacteria?

Accepted Answer

The spread of antibiotic resistance genes via plasmids between different bacterial species

Question 18

Which of the following best describes the role of an inducer in gene regulation?

Accepted Answer

It binds to a repressor protein, causing it to release from the operator and allowing gene expression.

Question 19

A mutation in the lac operon prevents the repressor from binding to the operator. What is the most likely outcome?

Accepted Answer

The structural genes will be continuously expressed, even in the absence of lactose.

Question 20

Which of the following is a correct pairing of a domain and a characteristic organism?

Accepted Answer

Eukarya – Fungi

Microbiology Study Guide: Key Concepts and Learning Objectives

Study Guide - Practice Questions

Study Guide - Flashcards