Q: Which of the following equations correctly represents the net ATP yield from glycolysis per molecule of glucose?

$2 \rightarrow 2 \text{ pyruvate} + 2 \text{ ATP} + 2 \text{ NADH}$

Question 1

Which of the following best describes the role of a repressor gene in microbial genetics?

Accepted Answer

Codes for a protein that binds to the operator and inhibits gene expression when product accumulates.

Question 2

A scientist wants to separate DNA fragments by size. Which molecular technique should they use, and what is the principle behind it?

Accepted Answer

Gel electrophoresis; DNA fragments are separated by movement through a gel under an electric field, with smaller fragments moving faster.

Question 3

Which of the following equations correctly represents the net ATP yield from glycolysis per molecule of glucose?

Accepted Answer

$2 ightarrow 2 	ext{ pyruvate} + 2 	ext{ ATP} + 2 	ext{ NADH}$

Question 4

Which statement best explains why autoclaving is considered a sterilization method?

Accepted Answer

It destroys all life forms, including spores, by using moist heat under pressure.

Question 5

A patient is prescribed a broad-spectrum antibiotic. Which of the following is a potential risk associated with this therapy?

Accepted Answer

Destruction of normal microbiota, leading to secondary infections.

Question 6

Which of the following best describes the difference between phototrophs and chemotrophs?

Accepted Answer

Phototrophs use light as an energy source; chemotrophs use chemicals.

Question 7

During which phase of the bacterial growth curve does the population size remain constant, and why?

Accepted Answer

Stationary phase; because the rate of cell division equals the rate of cell death due to nutrient depletion.

Question 8

Which of the following transport mechanisms requires ATP and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 9

A researcher is testing the effect of a new disinfectant on vegetative bacterial cells. Which term best describes the process if the disinfectant only kills vegetative pathogens on inanimate objects?

Accepted Answer

Disinfection

Question 10

Which of the following statements about enzyme inhibition is correct?

Accepted Answer

Noncompetitive inhibitors bind at a site other than the active site, causing loss of enzyme function.

Question 11

Which chemical agent is most likely to disrupt microbial membranes by denaturing proteins and is commonly used in hand sanitizers?

Accepted Answer

Phenolics

Question 12

A hospital uses HEPA filters in its ventilation system. What is the primary purpose of these filters?

Accepted Answer

To remove microbes from the air by filtration.

Question 13

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

Accepted Answer

It is the DNA sequence where the repressor protein binds to regulate gene expression.

Question 14

Which of the following is a correct description of the Calvin cycle?

Accepted Answer

It produces glucose from carbon dioxide.

Question 15

A patient is infected with a bacterium that produces beta-lactamase. Which of the following best explains why penicillin is ineffective?

Accepted Answer

Beta-lactamase inactivates penicillin by breaking its beta-lactam ring.

Question 16

Which of the following is the best definition of a transgenic organism (GMO)?

Accepted Answer

An organism containing foreign DNA from another species.

Question 17

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation regenerates NAD+ and yields 2 ATP per glucose.

Question 18

A scientist is using PCR to amplify a gene of interest. Which component is essential for the specificity of the reaction?

Accepted Answer

DNA primers

Question 19

Which of the following best describes the concept of selective toxicity in antimicrobial therapy?

Accepted Answer

The drug targets microbial cells while minimizing harm to host cells.

Question 20

Which of the following is a plausible consequence of antibiotic misuse?

Accepted Answer

Promotion of antibiotic resistance in microbial populations.

Essential Concepts in Introductory Microbiology

Study Guide - Practice Questions

Study Guide - Flashcards