Question 1

Which of the following features is present in eukaryotic cells but absent in prokaryotic cells?

Accepted Answer

Membrane-bound organelles

Question 2

A microbiologist isolates a bacterium with a thick peptidoglycan layer, teichoic acids, and no outer membrane. What color would you expect this bacterium to appear after Gram staining?

Accepted Answer

Purple

Question 3

Which of the following best explains why penicillin is more effective against Gram-positive bacteria than Gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer that is the primary target of penicillin

Question 4

A patient is diagnosed with pneumonia caused by Streptococcus pneumoniae. The strain isolated lacks a capsule. What is the most likely consequence of this absence?

Accepted Answer

The bacterium will be more easily phagocytosed by immune cells

Question 5

Which structure allows Neisseria gonorrhoeae to adhere to human mucosal surfaces, contributing to its pathogenicity?

Accepted Answer

Fimbriae

Question 6

A bacterium is described as a 'coccobacillus.' Which of the following best describes its shape?

Accepted Answer

Intermediate between spherical and rod-shaped

Question 7

Which of the following is a function of the bacterial glycocalyx when present as a capsule?

Accepted Answer

Enhances resistance to phagocytosis by host immune cells

Question 8

Which of the following statements about bacterial endospores is TRUE?

Accepted Answer

They allow certain Gram-positive bacteria to survive harsh conditions

Question 9

A patient presents with symptoms of Lyme disease. Which bacterial structure is most directly involved in the motility of the causative agent, Borreliella burgdorferi?

Accepted Answer

Axial filaments

Question 10

Which of the following best describes the genetic material of a typical prokaryotic cell?

Accepted Answer

One circular DNA molecule not enclosed by a membrane

Question 11

Which antibiotic targets the bacterial ribosome and is effective because of the structural differences between prokaryotic and eukaryotic ribosomes?

Accepted Answer

Streptomycin

Question 12

A Gram-negative bacterium is less susceptible to lysozyme than a Gram-positive bacterium. What structural feature accounts for this difference?

Accepted Answer

Outer membrane exterior to the peptidoglycan

Question 13

Which of the following is a distinguishing feature of Mycoplasma pneumoniae compared to most other bacteria?

Accepted Answer

Lack of a cell wall

Question 14

A scientist is studying a bacterium that stains red in the Gram stain, contains lipopolysaccharides, and is resistant to penicillin. Which of the following equations best represents the relationship between the thickness of the peptidoglycan layer ($$t) $$and the effectiveness of penicillin ($$E) in $$Gram-negative bacteria?

Accepted Answer

$$E is $$low when $$t is $$low and an outer membrane is present

Question 15

Which of the following best explains why polymyxins have a narrow therapeutic index?

Accepted Answer

They target the outer membrane of Gram-negative bacteria, but can also disrupt human cell membranes

Question 16

Which of the following arrangements describes a cluster of spherical bacterial cells?

Accepted Answer

Staphylococci

Question 17

A bacterium is found to possess a plasmid encoding antibiotic resistance. Which of the following structures is most likely involved in the transfer of this plasmid to another bacterium?

Accepted Answer

Pili

Question 18

Which of the following statements about the evolution of eukaryotes is supported by the presence of membrane-bound organelles?

Accepted Answer

Eukaryotes likely evolved from prokaryotic ancestors that developed internal membrane systems

Question 19

Which of the following is a correct match between a bacterial structure and its function?

Accepted Answer

Capsule – protection from phagocytosis

Question 20

A patient is treated with erythromycin for a bacterial infection. Which cellular component is the primary target of this antibiotic?

Accepted Answer

Bacterial ribosome

Functional Anatomy of Prokaryotic and Eukaryotic Cells: An Overview

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