Question 1

Which scientist is credited with disproving the theory of spontaneous generation using a swan-neck flask experiment?

Accepted Answer

Louis Pasteur

Question 2

Which of the following statements best describes a key difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have a nucleus, while prokaryotic cells lack a nucleus.

Question 3

A Gram-negative bacterium is observed under a microscope. Which structural feature is most likely present in its cell wall?

Accepted Answer

An outer membrane containing lipopolysaccharides

Question 4

Which of the following is NOT one of Koch's postulates?

Accepted Answer

The microorganism must cause disease only in animals, not humans.

Question 5

Which process is responsible for the synthesis of ATP during glycolysis?

Accepted Answer

Substrate-level phosphorylation

Question 6

A bacterial culture is grown in a medium containing only glucose as a carbon source. After 24 hours, the pH of the medium drops significantly. What is the most likely explanation for this observation?

Accepted Answer

The bacteria are fermenting glucose, producing acidic byproducts.

Question 7

Which of the following best describes the function of the bacterial flagellum?

Accepted Answer

Motility through rotation powered by a proton gradient

Question 8

During the stationary phase of the bacterial growth curve, which of the following is occurring?

Accepted Answer

The rate of cell division equals the rate of cell death.

Question 9

Which of the following is a correct description of competitive inhibition in enzyme activity?

Accepted Answer

An inhibitor competes with the substrate for the active site.

Question 10

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

Accepted Answer

$2 	ext{ ATP}$

Question 11

A patient presents with a bacterial infection. The causative agent is identified as Gram-positive. Which of the following is a clinical implication of this finding?

Accepted Answer

The bacterium is more susceptible to antibiotics targeting peptidoglycan synthesis.

Question 12

Which of the following best explains why obligate anaerobes cannot survive in the presence of oxygen?

Accepted Answer

They lack enzymes such as superoxide dismutase and catalase to detoxify reactive oxygen species.

Question 13

Which of the following is a function of the cytoplasmic membrane in bacteria?

Accepted Answer

Selective permeability for transport of molecules

Question 14

Which of the following best describes the streak plate method in microbiology?

Accepted Answer

A method for isolating pure colonies from a mixed culture

Question 15

Which of the following statements about the endosymbiotic theory is correct?

Accepted Answer

It proposes that mitochondria and chloroplasts originated from free-living prokaryotes.

Question 16

Which of the following is a product of fermentation in bacteria?

Accepted Answer

Lactic acid

Question 17

Which of the following best describes the function of ribosomes in prokaryotic cells?

Accepted Answer

Protein synthesis by translating mRNA

Question 18

Which of the following is a correct description of binary fission?

Accepted Answer

A process where a single cell divides into two identical daughter cells

Question 19

Which of the following is a major function of the bacterial capsule?

Accepted Answer

Protecting against phagocytosis by host immune cells

Question 20

Which of the following equations represents the conversion of nitrogen gas to ammonia by nitrogen-fixing bacteria?

Accepted Answer

$N_2 + 8H^+ + 8e^- \rightarrow 2NH_3 + H_2$

Microbiology Exam 1 Study Guide: Chapters 1–6

Study Guide - Practice Questions

Study Guide - Flashcards