Question 1

Which of the following statements best explains why viruses are considered acellular and not alive?

Accepted Answer

Viruses lack cellular structures and can only replicate inside a host cell.

Question 2

A bacterium is observed to have a thick peptidoglycan layer, teichoic acids, and stains purple in a Gram stain. Which type of cell wall does it possess?

Accepted Answer

Gram-positive

Question 3

Which of the following best describes the arrangement and function of bacterial flagella in chemotaxis?

Accepted Answer

Flagella alternate between clockwise (tumble) and counterclockwise (run) rotations to direct movement.

Question 4

Which of the following structures is responsible for the transfer of plasmid DNA between bacterial cells during conjugation?

Accepted Answer

Pili

Question 5

A patient is diagnosed with tuberculosis. Which unique cell wall component is detected by the acid-fast stain in the causative organism?

Accepted Answer

Mycolic acid

Question 6

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

Accepted Answer

It lacks a cell wall entirely.

Question 7

Which of the following is a function of the bacterial capsule (glycocalyx)?

Accepted Answer

Prevents drying out and protects against phagocytosis

Question 8

A bacterium is found to survive extreme heat, drying, and radiation. Which structure is most likely responsible for this resistance?

Accepted Answer

Endospore

Question 9

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 10

Which of the following is a distinguishing feature of Gram-negative bacteria compared to Gram-positive bacteria?

Accepted Answer

Outer membrane containing lipopolysaccharide (LPS)

Question 11

A dental biofilm is primarily composed of which bacterial structures that facilitate attachment to teeth and each other?

Accepted Answer

Fimbriae and glycocalyces

Question 12

Which of the following best describes the arrangement 'streptobacillus'?

Accepted Answer

A chain of rod-shaped cells

Question 13

Which of the following is true regarding plasmids in bacteria?

Accepted Answer

They often carry genes for antibiotic resistance and virulence.

Question 14

Which of the following best explains why Gram-negative bacteria can cause endotoxic shock?

Accepted Answer

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

Question 15

Which of the following is a correct statement about the nucleoid region in prokaryotic cells?

Accepted Answer

It contains a singular, circular chromosome.

Question 16

Which of the following best describes the function of inclusions in bacterial cells?

Accepted Answer

Storage of nutrients and other molecules

Question 17

Which of the following is a key difference between the cell membranes of eukaryotes and prokaryotes?

Accepted Answer

Eukaryotic membranes contain steroids such as cholesterol or ergosterol.

Question 18

A bacterium with peritrichous flagella is most likely to:

Accepted Answer

Have flagella distributed all over its surface

Question 19

Which of the following best describes the role of fimbriae in bacterial pathogenesis?

Accepted Answer

Enable attachment to host tissues and surfaces

Question 20

Which of the following is a correct statement about eukaryotic cell walls?

Accepted Answer

Fungi have cell walls, but animal cells do not.

Cell Structure and Function: Prokaryotic and Eukaryotic Microorganisms

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