Question 1

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

Accepted Answer

Eukaryotic cells have paired chromosomes within a membrane-bound nucleus, while prokaryotic cells have a single circular chromosome not enclosed by a membrane.

Question 2

Which structure allows certain bacteria to survive extreme environmental conditions such as boiling for up to 20 hours?

Accepted Answer

Endospore

Question 3

A bacterium is observed to have a helical, flexible shape and moves by means of an internal axial filament. Which group does it most likely belong to?

Accepted Answer

Spirochetes

Question 4

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

Accepted Answer

Prevents phagocytosis by host immune cells

Question 5

Which of the following best describes the composition of a Gram-positive bacterial cell wall?

Accepted Answer

A thick peptidoglycan layer with teichoic acids and no outer membrane

Question 6

Which of the following antibiotics specifically targets the cross-linking of peptidoglycan in bacterial cell walls?

Accepted Answer

Penicillin

Question 7

A scientist isolates a microorganism that lacks a cell wall, is pleomorphic, and contains sterols in its plasma membrane. Which genus does this organism most likely belong to?

Accepted Answer

Mycoplasma

Question 8

Which of the following best explains why Gram-negative bacteria are generally more resistant to antibiotics than Gram-positive bacteria?

Accepted Answer

They possess an outer membrane that restricts entry of many antibiotics.

Question 9

Which of the following arrangements describes cocci that divide in multiple planes and form grape-like clusters?

Accepted Answer

Staphylococci

Question 10

Which of the following is a distinguishing feature of Archaea compared to Bacteria?

Accepted Answer

Ability to live in extreme environments and unique membrane lipids

Question 11

Which of the following structures is responsible for the transfer of genetic material between bacterial cells during conjugation?

Accepted Answer

Pilus (Pili)

Question 12

A bacterium is described as 'peritrichous.' What does this indicate about its flagella?

Accepted Answer

It has flagella distributed over the entire cell surface.

Question 13

Which of the following best describes the function of carboxysomes in prokaryotic cells?

Accepted Answer

Site of CO$$_2$$ fixation via ribulose 1,5-diphosphate carboxylase

Question 14

Which of the following is true regarding the process of binary fission in prokaryotes?

Accepted Answer

It results in two genetically identical daughter cells.

Question 15

Which of the following is a unique feature of eukaryotic flagella compared to prokaryotic flagella?

Accepted Answer

Contains a 9+2 arrangement of microtubules made of tubulin

Question 16

Which of the following best describes the role of lipopolysaccharide (LPS) in Gram-negative bacteria?

Accepted Answer

It acts as an endotoxin and provides antigenic specificity.

Question 17

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

Accepted Answer

Mycolic acid

Question 18

Which of the following best explains why Mycoplasma pneumoniae is pleomorphic?

Accepted Answer

It lacks a cell wall and contains sterols in its membrane.

Question 19

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

Accepted Answer

Protein synthesis

Question 20

Which of the following best describes the arrangement of chromosomes in eukaryotic cells?

Accepted Answer

Paired linear chromosomes within a membrane-bound nucleus

Microbial Structure: Prokaryotic and Eukaryotic Cells

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