Question 1

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

Accepted Answer

Prokaryotic cells have a single circular chromosome not enclosed in a nuclear membrane.

Question 2

A bacterium is isolated from a hot spring and is found to have pseudomurein in its cell wall and a unique rRNA signature. To which domain does this organism most likely belong?

Accepted Answer

Domain Archaea

Question 3

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

Accepted Answer

Their outer membrane contains lipopolysaccharide (LPS), which can act as an endotoxin.

Question 4

A patient presents with symptoms of food poisoning after eating undercooked meat. The causative agent is a Gram-positive, endospore-forming, rod-shaped bacterium. Which genus is most likely responsible?

Accepted Answer

Bacillus

Question 5

Which of the following best explains why Mycoplasma species are resistant to antibiotics that target cell wall synthesis?

Accepted Answer

They lack a cell wall entirely.

Question 6

During a Gram stain, why do Gram-positive bacteria retain the crystal violet-iodine complex after the alcohol wash?

Accepted Answer

Their thick peptidoglycan layer is dehydrated by alcohol, trapping the dye complex.

Question 7

Which structure allows bacteria to transfer genetic material directly from one cell to another?

Accepted Answer

Pili

Question 8

A bacterium is observed to move toward a chemical attractant. Which term best describes this behavior, and what structure is primarily responsible?

Accepted Answer

Chemotaxis; flagella

Question 9

Which of the following is a correct pairing of a fungal characteristic with its bacterial counterpart?

Accepted Answer

Fungi are eukaryotic; bacteria are prokaryotic.

Question 10

A patient develops a deep fungal infection after a bone marrow transplant. Which type of mycosis is this?

Accepted Answer

Systemic mycosis

Question 11

Which of the following best describes the cell wall composition of diatoms?

Accepted Answer

Pectin and a layer of silica

Question 12

A shellfish poisoning outbreak is traced to a neurotoxin produced by a type of planktonic algae. Which group is most likely responsible?

Accepted Answer

Dinoflagellates

Question 13

Which of the following is a distinguishing feature of protozoa compared to bacteria?

Accepted Answer

Protozoa are chemoheterotrophic and motile, often forming cysts.

Question 14

A patient is diagnosed with giardiasis after drinking contaminated water. Which of the following best describes the organism responsible?

Accepted Answer

A flagellated protozoan that forms cysts and trophozoites

Question 15

Which of the following statements about endospores is correct?

Accepted Answer

Endospores are resistant to desiccation, heat, and chemicals.

Question 16

Which of the following best explains why lysozyme is effective against Gram-positive bacteria?

Accepted Answer

Lysozyme digests the disaccharide in peptidoglycan, which is abundant in Gram-positive cell walls.

Question 17

Which of the following is a correct description of the arrangement and shape of Streptococci?

Accepted Answer

Spherical cells arranged in chains

Question 18

A scientist is studying a bacterium with a periplasmic space, thin peptidoglycan layer, and an outer membrane. Which type of bacterium is this?

Accepted Answer

Gram-negative bacterium

Question 19

Which of the following equations correctly represents the relationship between the size of a typical prokaryotic cell and a eukaryotic cell?

Accepted Answer

$$0.2\ \mu m \leq 	ext{Prokaryote size} \leq 8\ \mu m$$

Question 20

Which of the following best describes the function of teichoic acids in Gram-positive bacteria?

Accepted Answer

They link the peptidoglycan to the plasma membrane and regulate cation movement.

Prokaryotic and Eukaryotic Cells: Structure, Classification, and Morphology

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