Question 1

Which of the following best describes the function of a bacterial capsule in relation to human health?

Accepted Answer

It protects bacteria from phagocytosis by host immune cells, enhancing pathogenicity.

Question 2

A patient is infected with a Gram-negative bacterium. Which structural feature of the cell wall is most clinically significant in this context?

Accepted Answer

An outer membrane containing lipopolysaccharide (LPS), which can act as an endotoxin.

Question 3

Which of the following statements correctly distinguishes between bacterial fimbriae and pili?

Accepted Answer

Pili are usually longer and fewer in number than fimbriae, and are involved in conjugation.

Question 4

A microbiologist observes a bacterium with a single flagellum at each end of the cell. What is the correct term for this flagellar arrangement?

Accepted Answer

Amphitrichous

Question 5

Which of the following best explains why Gram-negative bacteria are generally more resistant to antibiotics that target peptidoglycan synthesis?

Accepted Answer

Their outer membrane acts as a barrier to many antibiotics.

Question 6

Which of the following equations correctly represents the osmotic pressure ($$\Pi) $$across a cytoplasmic membrane, where $$C is $$the molar concentration, $$R is $$the gas constant, and $$T is $$the temperature in Kelvin?

Accepted Answer

$$\Pi = CRT$$

Question 7

A bacterium is placed in a solution and water begins to flow into the cell, causing it to swell. Which type of solution is the bacterium in?

Accepted Answer

Hypotonic

Question 8

Which of the following is a key difference between prokaryotic and eukaryotic ribosomes?

Accepted Answer

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

Question 9

Which of the following best describes the fluid mosaic model of membrane structure?

Accepted Answer

A double layer of phospholipids with proteins embedded, allowing lateral movement.

Question 10

Which process requires energy input from the cell to move substances across the cytoplasmic membrane against their concentration gradient?

Accepted Answer

Active transport

Question 11

Which of the following is a function of the eukaryotic Golgi body?

Accepted Answer

Modification, packaging, and sorting of proteins for secretion or delivery to other organelles.

Question 12

A scientist is studying a cell that lacks a nucleus, has a single circular chromosome, and contains 70S ribosomes. Which type of cell is being observed?

Accepted Answer

Prokaryotic cell

Question 13

Which of the following best describes the structure of peptidoglycan in bacterial cell walls?

Accepted Answer

A network of polysaccharide chains cross-linked by short peptides.

Question 14

Which of the following is NOT a function of the bacterial cytoplasmic membrane?

Accepted Answer

Synthesis of peptidoglycan

Question 15

Which of the following statements about endospores is correct?

Accepted Answer

Endospores are resistant to heat, desiccation, and chemicals, allowing survival in harsh conditions.

Question 16

Which of the following is a key piece of evidence supporting the endosymbiotic theory for the origin of mitochondria?

Accepted Answer

Mitochondria contain circular DNA similar to bacterial chromosomes.

Question 17

Which of the following best describes the difference between exocytosis and endocytosis in eukaryotic cells?

Accepted Answer

Exocytosis moves substances out of the cell, while endocytosis brings substances in.

Question 18

Which of the following correctly matches a eukaryotic cytoskeletal filament with its function?

Accepted Answer

Microtubules: provide structural support and serve as tracks for organelle movement.

Question 19

A eukaryotic cell engulfs a bacterium using extensions of its membrane. What are these extensions called, and what process is occurring?

Accepted Answer

Pseudopods; phagocytosis

Question 20

Which of the following best explains why antibiotics that target 70S ribosomes are generally effective against bacteria but not human cells?

Accepted Answer

Human cells have 80S ribosomes, which differ structurally from bacterial 70S ribosomes.

Ch 3: Cell Structure and Function: Study Guide for Microbiology

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