Question 1

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

Accepted Answer

Prokaryotic cells lack a nucleus, allowing them to read DNA and make protein simultaneously.

Question 2

A bacterium is found to have a thick layer of peptidoglycan and teichoic acids in its cell wall. After Gram staining, what color will it appear and why?

Accepted Answer

Purple, because the thick peptidoglycan layer retains the crystal violet stain.

Question 3

Which component of the Gram-negative bacterial cell wall is responsible for causing fever, vasodilation, and shock in infected patients?

Accepted Answer

Lipid A portion of lipopolysaccharide (LPS)

Question 4

A scientist observes a bacterium moving toward a nutrient source. Which structure is primarily responsible for this movement, and what is the process called?

Accepted Answer

Flagella; taxis

Question 5

Which of the following best describes the function of bacterial capsules?

Accepted Answer

They are firmly attached and may prevent bacteria from being recognized by the host immune system.

Question 6

A bacterial cell is placed in a hypertonic solution. Predict the direction of water movement and the likely outcome for the cell.

Accepted Answer

Water will move out of the cell, causing it to shrink (plasmolysis).

Question 7

Which process involves the chemical modification of a substance as it is transported into a bacterial cell?

Accepted Answer

Group translocation

Question 8

A patient is infected with a bacterium that lacks a cell wall. Which antibiotic would likely be ineffective against this organism, and why?

Accepted Answer

Penicillin, because it targets peptidoglycan synthesis.

Question 9

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

Accepted Answer

Their outer membrane acts as a barrier to many drugs.

Question 10

Which structure is directly involved in the transfer of DNA between bacterial cells during conjugation?

Accepted Answer

Pili

Question 11

A researcher is studying a biofilm formed on a medical device. Which bacterial structure is most important for the initial adherence of bacteria to the device?

Accepted Answer

Fimbriae

Question 12

Which of the following is a function of the bacterial cytoplasmic membrane?

Accepted Answer

Acts as a selectively permeable barrier and maintains electrical gradients.

Question 13

A bacterial cell is placed in a solution where the concentration of solutes is lower outside the cell than inside. What will happen to the cell?

Accepted Answer

Water will move into the cell, possibly causing it to burst.

Question 14

Which of the following best describes the fluid mosaic model of the cytoplasmic membrane?

Accepted Answer

A dynamic structure with proteins embedded in or associated with a phospholipid bilayer.

Question 15

Which of the following transport processes requires energy and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 16

A bacterium is observed to have only one or two long, hair-like structures that are longer than fimbriae but shorter than flagella. What is the most likely function of these structures?

Accepted Answer

DNA transfer during conjugation

Question 17

Which of the following equations best represents the net movement of water during osmosis across a semipermeable membrane?

Accepted Answer

$$J_{water} = L_p (\Delta P - \sigma \Delta \pi)$$

Question 18

Which of the following is NOT a characteristic of prokaryotic cells?

Accepted Answer

They have internal membrane-bound organelles.

Question 19

A bacterial cell is exposed to an antibiotic that targets the synthesis of teichoic acids. Which type of bacteria would be most affected?

Accepted Answer

Gram-positive bacteria

Question 20

Which of the following best explains why acid-fast bacteria are resistant to desiccation?

Accepted Answer

They contain up to 60% mycolic acid in their cell walls.

Cell Structure and Function in Microbiology

Study Guide - Practice Questions

Study Guide - Flashcards