Question 1

Which of the following statements correctly distinguishes prokaryotic cells from eukaryotic cells?

Accepted Answer

Prokaryotic cells lack a nucleus and have ribosomes that are 70S, while eukaryotic cells have a nucleus and ribosomes that are 80S.

Question 2

Which structure in Gram-negative bacteria is responsible for severe symptoms during systemic infections, such as fever and shock?

Accepted Answer

Lipopolysaccharide (LPS), specifically Lipid A

Question 3

A bacterium is placed in a hypotonic solution. What feature primarily prevents it from lysing?

Accepted Answer

Cell wall composed of peptidoglycan

Question 4

Which of the following best describes the function of conjugative pili in bacteria?

Accepted Answer

They facilitate the transfer of DNA between bacteria during conjugation.

Question 5

A protozoan living in a hypotonic environment must expend energy to avoid lysis. What cellular structure is primarily involved in this process?

Accepted Answer

Contractile vacuole

Question 6

Which of the following is a correct description of facilitated diffusion in bacterial cells?

Accepted Answer

Movement of molecules down their concentration gradient via a specific transporter protein, without energy input.

Question 7

Which bacterial shape is described as helical and flexible, often possessing axial filaments for motility?

Accepted Answer

Spirochete

Question 8

A bacterium quickly metabolizes glucose after uptake to prevent it from diffusing back out. What process is this an example of?

Accepted Answer

Group translocation

Question 9

Which of the following statements about Mycoplasma is correct?

Accepted Answer

Mycoplasma lacks a cell wall, making it susceptible to osmotic lysis.

Question 10

Which of the following best explains why Gram-negative bacteria can cause more severe systemic symptoms than Gram-positive bacteria?

Accepted Answer

Gram-negative bacteria possess Lipid A in their lipopolysaccharide, which is toxic when released during infection.

Question 11

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

Accepted Answer

Facilitation of DNA transfer during conjugation

Question 12

A scientist isolates a cell with 80S ribosomes and a cell wall made of cellulose. Which type of organism is most likely being studied?

Accepted Answer

Plant cell

Question 13

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

Accepted Answer

It serves as a variable antigenic determinant for serotyping bacteria.

Question 14

Which of the following transport mechanisms in bacteria requires energy and moves molecules against their concentration gradient?

Accepted Answer

Active transport

Question 15

A protozoan is observed ingesting whole bacterial cells. What property of protozoan cell structure allows this behavior?

Accepted Answer

Flexibility of the cell surface

Question 16

Which equation best represents the process of osmosis in cells?

Accepted Answer

$$\Delta \Psi = \Psi_{inside} - \Psi_{outside}$$

Question 17

Which of the following is a correct statement about bacterial plasmids?

Accepted Answer

Plasmids are autonomously replicating, circular DNA molecules containing non-essential genes.

Question 18

Which of the following best describes the function of fimbriae in bacteria?

Accepted Answer

Adherence to surfaces

Question 19

A bacterial cell is placed in a hypertonic solution. What is the most likely outcome?

Accepted Answer

The cell will undergo plasmolysis as water leaves the cell.

Question 20

Which of the following is a correct description of the bacterial cell wall?

Accepted Answer

It is composed of peptidoglycan in most bacteria.

Cell Structure and Physiology in Microbiology ~ Chp 4 - 2

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