Question 1

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

Accepted Answer

Gram-negative bacteria possess an outer membrane containing lipopolysaccharides and porin proteins, which act as an extra barrier.

Question 2

A microbiologist stains a bacterial sample and observes blue/purple cells under the microscope. Which structural feature is most likely present in these cells?

Accepted Answer

A thick peptidoglycan layer and no outer membrane

Question 3

Which of the following best describes the process of binary fission in prokaryotes?

Accepted Answer

The cell copies its DNA, grows, and forms a septum that separates two genetically identical daughter cells.

Question 4

Which of the following equations best represents the rate of simple diffusion across a prokaryotic plasma membrane?

Accepted Answer

$$J = -D \frac{dC}{dx}$$

Question 5

Which prokaryotic structure is primarily responsible for motility and can be arranged as monotrichous, lophotrichous, amphitrichous, or peritrichous?

Accepted Answer

Flagella

Question 6

A bacterium moves toward a higher concentration of glucose. Which term best describes this behavior?

Accepted Answer

Chemotaxis

Question 7

Which of the following statements about Archaea is correct?

Accepted Answer

Archaea are more closely related to domain Eukarya than to bacteria.

Question 8

A Gram-negative bacterium is exposed to an antimicrobial agent that targets peptidoglycan. Which feature may allow it to survive better than a Gram-positive bacterium?

Accepted Answer

Its outer membrane acts as a barrier, limiting agent access to peptidoglycan.

Question 9

Which of the following is NOT a function of membrane proteins in prokaryotic plasma membranes?

Accepted Answer

Synthesizing peptidoglycan outside the cell

Question 10

A prokaryotic cell is placed in a hypotonic solution. Which process will most likely occur?

Accepted Answer

Water will enter the cell by osmosis, potentially causing it to swell.

Question 11

Which of the following best describes the composition of the prokaryotic plasma membrane?

Accepted Answer

A phospholipid bilayer with embedded proteins and carbohydrates

Question 12

Which structure allows prokaryotes to adhere to surfaces and participate in gene transfer via conjugation?

Accepted Answer

Pili

Question 13

Which of the following is a distinguishing feature of acid-fast bacteria?

Accepted Answer

They stain pink with the acid-fast stain due to their unique cell wall composition.

Question 14

Which of the following cell shapes is correctly matched with its description?

Accepted Answer

Vibrio: comma-shaped

Question 15

A bacterium forms a well-organized, tightly associated glycocalyx. What is this structure called and what is its primary function?

Accepted Answer

Capsule; helps bacteria adhere to host tissues and evade immune responses

Question 16

Which of the following statements about prokaryotic cell walls is correct?

Accepted Answer

Archaea may have cell walls made of polysaccharides, pure protein, or lack cell walls entirely.

Question 17

Which of the following best describes the fluid-mosaic model of the prokaryotic plasma membrane?

Accepted Answer

Membrane lipids and proteins move freely, allowing proteins to relocate where needed.

Question 18

Which of the following is a major function of endospores in bacteria?

Accepted Answer

Protecting genetic material during harsh environmental conditions

Question 19

Which of the following best describes the difference between monomorphic and pleomorphic bacteria?

Accepted Answer

Monomorphic bacteria have one shape; pleomorphic bacteria can take on different forms.

Question 20

Which of the following is a correct statement about prokaryotic ribosomes?

Accepted Answer

They are composed of small and large subunits and are found in the cytoplasm.

BIO Exam 1: Ch 3

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