Question 1

Which of the following statements best explains why Pasteur’s swan-neck flask experiment was pivotal in disproving spontaneous generation?

Accepted Answer

It demonstrated that sterilized broth remained free of microbial growth unless exposed to microorganisms from the air, supporting biogenesis.

Question 2

A patient is diagnosed with a bacterial infection. The bacteria are observed to have a thick peptidoglycan layer and no outer membrane. Which of the following is most likely true about these bacteria?

Accepted Answer

They are Gram-positive and will appear purple after Gram staining.

Question 3

Which of the following best describes the difference between prokaryotic and eukaryotic ribosomes?

Accepted Answer

Prokaryotic ribosomes are 70S, while eukaryotic ribosomes are 80S.

Question 4

A scientist isolates a microorganism with the following characteristics: it is unicellular, has a nucleus, and moves using pseudopodia. Which group does this organism most likely belong to?

Accepted Answer

Protozoa

Question 5

Which of the following is NOT a function of the normal microbiota in humans?

Accepted Answer

Directly causing disease in healthy individuals

Question 6

Which of the following structures is found in both prokaryotic and eukaryotic cells and is primarily responsible for controlling the movement of substances into and out of the cell?

Accepted Answer

Plasma membrane

Question 7

A patient presents with a fungal infection caused by Candida albicans. Which of the following statements about this organism is correct?

Accepted Answer

It is a yeast that reproduces primarily by budding.

Question 8

Which of the following best describes the process of sporulation in bacteria?

Accepted Answer

It is the formation of a highly resistant, dormant structure in response to adverse conditions.

Question 9

Which of the following is a key difference between the cell walls of fungi and bacteria?

Accepted Answer

Fungal cell walls contain chitin, while bacterial cell walls contain peptidoglycan.

Question 10

A virus is classified as an RNA virus with a helical capsid and an envelope. Which of the following best describes its structure?

Accepted Answer

It contains RNA, a helical protein capsid, and a lipid envelope derived from the host cell membrane.

Question 11

Which of the following best explains why Gram-negative bacteria are generally more resistant to certain antibiotics than Gram-positive bacteria?

Accepted Answer

They possess an outer membrane that acts as a barrier to many antibiotics.

Question 12

Which of the following is an example of a persistent viral infection?

Accepted Answer

Hepatitis B virus remaining in the liver for years with ongoing viral production

Question 13

A patient is diagnosed with malaria. Which protozoan is responsible for this disease, and how is it transmitted?

Accepted Answer

Plasmodium; transmitted by the bite of an Anopheles mosquito

Question 14

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that lack nucleic acids and cause diseases such as Creutzfeldt-Jakob disease.

Question 15

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

Accepted Answer

They are involved in motility and chemotaxis, allowing bacteria to move toward or away from stimuli.

Question 16

A laboratory technician is using Koch’s postulates to determine the cause of a new disease. Which step is essential to confirm that a specific microbe causes the disease?

Accepted Answer

The microbe must be isolated from a diseased host and grown in pure culture.

Question 17

Which of the following equations best represents the process of aerobic cellular respiration in mitochondria?

Accepted Answer

$$6\ \mathrm{O}_2 + \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 ightarrow 6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 	ext{energy}$$

Question 18

Which of the following is a correct statement about the role of arthropods in disease transmission?

Accepted Answer

Arthropods serve as vectors by transmitting pathogens between hosts.

Question 19

Which of the following best describes the difference between passive and active transport across the plasma membrane?

Accepted Answer

Passive transport moves substances down their concentration gradient without energy input, while active transport moves substances against their gradient using ATP.

Question 20

Which of the following is a real-world example of the ecological importance of microorganisms?

Accepted Answer

Bacteria in the soil fix atmospheric nitrogen into forms usable by plants: $$\mathrm{N}_2 \rightarrow \mathrm{NH}_3$$

Microbiology Study Guide: Key Concepts from Chapters 1, 4, 12, and 13

Study Guide - Practice Questions

Study Guide - Flashcards