Question 1

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

Accepted Answer

Eukaryotic cells have a nucleus containing their genetic material, while prokaryotic cells have their genetic material in a nucleoid region.

Question 2

A microbiologist isolates a microbe that is unicellular, lacks a nucleus, and has a cell wall containing peptidoglycan. To which group does this organism most likely belong?

Accepted Answer

Bacteria

Question 3

Which of the following statements about Gram-negative bacteria is correct?

Accepted Answer

They contain lipopolysaccharide (LPS) in their outer membrane, which can act as an endotoxin.

Question 4

Which of the following is a medically important reason why Mycoplasma species are naturally resistant to penicillin?

Accepted Answer

They lack a cell wall, so penicillin has no target to act upon.

Question 5

Which of the following best explains why Acid-Fast bacteria are difficult to stain and treat?

Accepted Answer

Their cell walls contain mycolic acids, making them waxy and impermeable to many stains and antibiotics.

Question 6

A patient develops a severe infection after taking broad-spectrum antibiotics, which disrupt their normal gut flora. This is an example of disease caused by:

Accepted Answer

Dysbiosis

Question 7

Which of the following is TRUE regarding biofilms?

Accepted Answer

Biofilms are communities of microbes attached to surfaces and embedded in a self-produced matrix, making them more resistant to antibiotics.

Question 8

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

Accepted Answer

Primary active transport

Question 9

Which of the following statements about endospores is correct?

Accepted Answer

Endospores are highly resistant, dormant structures formed by certain bacteria to survive harsh conditions.

Question 10

Which two genera of bacteria are medically relevant for their ability to form endospores?

Accepted Answer

Bacillus and Clostridium

Question 11

A scientist is classifying a newly discovered microbe using the binomial naming system. Which of the following is the correct way to write the name?

Accepted Answer

$$Escherichia~coli$$

Question 12

Which of the following best describes mutualism in the context of the human microbiome?

Accepted Answer

Both the human and the microbe benefit from the interaction.

Question 13

Which of the following statements about the Gram stain is correct?

Accepted Answer

It differentiates bacteria based on the thickness of their peptidoglycan layer.

Question 14

Which of the following is NOT a line of evidence supporting the endosymbiotic theory?

Accepted Answer

Mitochondria and chloroplasts have peptidoglycan cell walls.

Question 15

A single-celled organism is observed to have a nucleus, a cell wall, and no chloroplasts. It is nonmotile. In which kingdom is this organism most likely classified?

Accepted Answer

Fungi

Question 16

Which of the following statements about ribosomes is correct?

Accepted Answer

Both prokaryotes and eukaryotes use ribosomes for protein synthesis.

Question 17

Which of the following best describes the function of the plasma membrane in bacteria?

Accepted Answer

It acts as a selective barrier, controlling the movement of substances in and out of the cell.

Question 18

Which of the following is a complication of using a 97% sequence similarity cut-off when identifying microbes?

Accepted Answer

It may group genetically distinct species together, missing important differences.

Question 19

Which of the following is TRUE regarding the difference between true pathogens and opportunistic pathogens?

Accepted Answer

Opportunistic pathogens can cause disease when the host's defenses are compromised.

Question 20

Which of the following cell structures is present in both prokaryotes and eukaryotes and is responsible for synthesizing proteins?

Accepted Answer

Ribosome

MMBS111 Unit 1 Microbiology Study Guide – Step-by-Step Guidance

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