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 linkage of peptidoglycan in bacterial cell walls?

Accepted Answer

Alternating NAG and NAM subunits cross-linked by peptide bridges

Question 4

A patient is diagnosed with tuberculosis. Which unique cell wall component is responsible for the acid-fast property of the causative agent?

Accepted Answer

Mycolic acid

Question 5

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

Accepted Answer

Prevents phagocytosis by host immune cells

Question 6

Which structure allows bacteria to transfer plasmid DNA during conjugation?

Accepted Answer

Pili

Question 7

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

Accepted Answer

Endospore

Question 8

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

Accepted Answer

Prokaryotic ribosomes are 70S, eukaryotic ribosomes are 80S

Question 9

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

Accepted Answer

Presence of an outer membrane containing lipopolysaccharide

Question 10

A scientist observes a bacterium with a tuft of flagella at one end. What is the correct term for this flagellar arrangement?

Accepted Answer

Lophotrichous

Question 11

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.

Question 12

Which of the following is a function of bacterial fimbriae?

Accepted Answer

Attachment to surfaces and other cells

Question 13

Which of the following is true regarding the nucleoid region in prokaryotic cells?

Accepted Answer

It contains a singular, circular chromosome.

Question 14

Which of the following best describes the process of chemotaxis in bacteria?

Accepted Answer

Movement toward or away from a chemical stimulus by altering the length of runs and tumbles

Question 15

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 16

Which of the following is NOT a function of the bacterial cell wall?

Accepted Answer

Protein synthesis

Question 17

Which of the following statements about biofilms is correct?

Accepted Answer

Fimbriae and glycocalyces are important for biofilm formation.

Question 18

Which of the following best describes the role of plasmids in bacteria?

Accepted Answer

They often carry genes for antibiotic resistance and virulence factors.

Question 19

A patient with a prosthetic heart valve develops a persistent Staphylococcus aureus infection. Which bacterial structure is most likely contributing to the persistence of this infection?

Accepted Answer

Biofilm

Question 20

Which of the following equations correctly represents the composition of a prokaryotic ribosome?

Accepted Answer

$$50S + 30S = 70S$$

Cell Structure and Function in Microbiology: Prokaryotic and Eukaryotic Cells

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