Question 1

Which of the following best describes the function of a bacterial capsule?

Accepted Answer

It protects the cell from phagocytosis and aids in biofilm formation.

Question 2

A bacterium with flagella distributed all over its surface is described as:

Accepted Answer

Peritrichous

Question 3

Which adaptation makes bacterial endospores highly resistant to harsh environmental conditions?

Accepted Answer

Presence of dipicolinic acid and calcium ions

Question 4

During chemotaxis, how do peritrichously flagellated bacteria move toward an attractant?

Accepted Answer

By alternating between runs and tumbles, with longer runs when moving up the attractant gradient

Question 5

Which of the following statements correctly contrasts bacterial and archaeal flagella?

Accepted Answer

Bacterial flagella are composed of flagellin, while archaeal flagella (archaella) are composed of different proteins and are structurally similar to type IV pili.

Question 6

Which of the following is NOT a function of the bacterial glycocalyx?

Accepted Answer

Synthesis of ATP

Question 7

A laboratory technician observes a bacterium that moves in a corkscrew fashion. Which structure is most likely responsible for this type of motility?

Accepted Answer

Periplasmic (endoflagella) flagella

Question 8

Which of the following best explains why endospores are considered the most resistant cellular structures known?

Accepted Answer

They contain dipicolinic acid, calcium ions, and small acid-soluble spore proteins (SASPs) that protect DNA.

Question 9

Which of the following arrangements describes a bacterium with a single flagellum at each end?

Accepted Answer

Amphitrichous

Question 10

A patient is infected with a strain of Escherichia coli that is identified as O157:H7. The 'H7' designation refers to:

Accepted Answer

The specific flagellar antigen

Question 11

Which of the following best describes the energy source for rotation of the bacterial flagellum?

Accepted Answer

Proton motive force across the cytoplasmic membrane

Question 12

Which of the following is a key difference between a capsule and a slime layer?

Accepted Answer

Capsules are neatly organized and firmly attached, while slime layers are unorganized and loosely attached.

Question 13

Which of the following mechanisms allows bacteria to move over solid surfaces independently of flagella?

Accepted Answer

Gliding motility using surface proteins or type IV pili

Question 14

During endospore formation, which of the following events occurs LAST?

Accepted Answer

Release of the mature endospore from the mother cell

Question 15

A bacterium is exposed to a sudden increase in a repellent chemical. What is the expected immediate response in its motility pattern?

Accepted Answer

Increased frequency of tumbles

Question 16

Which of the following best explains why bacteria perform a 'biased random walk' during chemotaxis?

Accepted Answer

They respond to temporal changes in chemical concentration, increasing run length when moving toward attractants.

Question 17

Which of the following is NOT a characteristic of bacterial endospores compared to vegetative cells?

Accepted Answer

High water content

Question 18

A researcher is studying a bacterium that moves by extending and retracting pili. Which type of motility is being observed?

Accepted Answer

Twitching motility

Question 19

Which of the following best describes the assembly of bacterial flagella?

Accepted Answer

Flagellin subunits are transported through a central channel and added at the tip.

Question 20

Which of the following is a real-world consequence of capsule production in pathogenic bacteria?

Accepted Answer

Enhanced ability to evade the host immune system by preventing phagocytosis

Cell Surface Structures and Motility in Microbiology

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