Question 1

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

Accepted Answer

It demonstrated that microorganisms in the air were responsible for contaminating sterile solutions, supporting the theory of biogenesis.

Question 2

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 can reproduce asexually by budding.

Question 3

Which of the following structures is found in both prokaryotic and eukaryotic cells and is responsible for protein synthesis?

Accepted Answer

Ribosome

Question 4

A Gram-negative bacterium is more resistant to penicillin than a Gram-positive bacterium. Which structural feature accounts for this difference?

Accepted Answer

An outer membrane containing lipopolysaccharide

Question 5

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

Accepted Answer

They enable bacteria to survive extreme environmental conditions such as heat and desiccation.

Question 6

A scientist isolates a microorganism with the following characteristics: it is unicellular, lacks a nucleus, has a cell wall containing peptidoglycan, and reproduces by binary fission. To which group does this organism most likely belong?

Accepted Answer

Bacteria

Question 7

Which of the following is a correct statement about the plasma membrane of prokaryotic cells?

Accepted Answer

It regulates the movement of substances into and out of the cell via passive and active transport.

Question 8

Which of the following equations best represents the process of photosynthesis carried out by algae?

Accepted Answer

$$6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} \rightarrow C_6H_{12}O_6$ + 6\ \mathrm{O}_2$$

Question 9

Which of the following statements about Koch’s postulates is correct?

Accepted Answer

They provide a systematic method to link a specific microbe to a specific disease.

Question 10

A patient is diagnosed with malaria, a disease caused by Plasmodium species. Which of the following statements about this protozoan is correct?

Accepted Answer

It is transmitted to humans by the bite of an infected Anopheles mosquito.

Question 11

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 12

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 13

Which of the following best describes the lytic cycle of a bacteriophage?

Accepted Answer

The phage replicates inside the host cell and causes cell lysis, releasing new phages.

Question 14

Which of the following is a correct statement about prions?

Accepted Answer

They are infectious proteins that lack nucleic acids.

Question 15

A patient is infected with a virus that remains dormant in nerve cells and can reactivate years later, causing symptoms. Which type of infection is this, and which virus is a classic example?

Accepted Answer

Latent infection; Herpes simplex virus

Question 16

Which of the following best explains why normal microbiota are important for human health?

Accepted Answer

They compete with pathogens for nutrients and help stimulate the immune system.

Question 17

Which of the following statements about viral structure is correct?

Accepted Answer

Viral envelopes are derived from the host cell membrane and may contain viral spikes.

Question 18

Which of the following is a correct pairing of a medically important fungus and the disease it causes?

Accepted Answer

Cryptococcus – meningitis

Question 19

Which of the following best describes the role of arthropods in the transmission of infectious diseases?

Accepted Answer

They act as vectors, transmitting pathogens between hosts.

Question 20

A laboratory technician is tasked with quantifying the number of infectious viral particles in a sample. Which of the following methods is most appropriate for this purpose?

Accepted Answer

Plaque assay

Microbiology Study Guide: Foundations, Cell Structure, Eukaryotic Microbes, and Viruses

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