Question 1

Which of the following best explains why Mycobacterium tuberculosis is resistant to Gram staining?

Accepted Answer

Its cell wall contains mycolic acids and a thick waxy membranous layer that prevents dye penetration.

Question 2

During acid-fast staining, which step is responsible for removing carbolfuchsin from non-acid-fast cells?

Accepted Answer

Addition of acid alcohol

Question 3

A patient sample is stained and observed under a microscope. The cells appear red against a blue background. What can you conclude about the bacteria present?

Accepted Answer

They are acid-fast bacteria, likely Mycobacterium species.

Question 4

Which of the following statements about bacterial capsules is TRUE?

Accepted Answer

Capsules are made of polysaccharides and can inhibit ingestion by phagocytes.

Question 5

Why are capsules often lost during in vitro culture of pathogenic bacteria?

Accepted Answer

Environmental conditions in vitro do not induce capsule formation.

Question 6

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

Accepted Answer

They provide motility by rotating, powered by proton motive force.

Question 7

A bacterium is observed to have flagella distributed all over its surface. What is the correct term for this arrangement?

Accepted Answer

Peritrichous

Question 8

Which of the following is a key difference between eukaryotic and bacterial flagella?

Accepted Answer

Bacterial flagella rotate, while eukaryotic flagella bend.

Question 9

Which of the following best describes the role of pili in bacteria?

Accepted Answer

They facilitate the exchange of genetic material during conjugation.

Question 10

A bacterial strain is found to survive boiling, exposure to strong acids, and desiccation. Which structure is most likely responsible for this resistance?

Accepted Answer

Endospore

Question 11

Which of the following is TRUE regarding bacterial endospores?

Accepted Answer

They are metabolically inactive and highly resistant to environmental stress.

Question 12

Which of the following best explains why endospores are difficult to eradicate in clinical and food settings?

Accepted Answer

Endospores have a very dry core and protective layers that resist heat, chemicals, and radiation.

Question 13

Which of the following is a correct statement about plasmids in bacteria?

Accepted Answer

Plasmids are double-stranded, circular DNA molecules that can carry non-essential but advantageous genes.

Question 14

A researcher is studying a bacterial strain that forms a capsule only when grown in the presence of sucrose. What does this observation best illustrate?

Accepted Answer

Environmental factors can regulate the expression of certain bacterial structures.

Question 15

Which of the following is the primary function of the bacterial capsule in pathogenic species?

Accepted Answer

To inhibit ingestion and/or killing by phagocytes

Question 16

Which of the following best describes the process of germination in bacterial endospores?

Accepted Answer

It is the process by which a dormant endospore returns to a metabolically active vegetative cell.

Question 17

Which of the following is NOT a function of bacterial plasmids?

Accepted Answer

Carrying genes essential for basic cell metabolism

Question 18

A hospital outbreak is traced to a bacterium that survives routine disinfection and causes food poisoning. Which structure is most likely responsible for its persistence?

Accepted Answer

Endospores

Question 19

Which of the following best explains the movement of prokaryotic flagella?

Accepted Answer

They rotate like a propeller, powered by the proton motive force ($\Delta p$).

Question 20

Which of the following is a correct sequence for the acid-fast staining procedure?

Accepted Answer

Carbolfuchsin → Acid alcohol → Methylene blue

Further Bacterial Cell Features and the Endospore

Study Guide - Practice Questions

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