Question 1

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

Accepted Answer

Prokaryotic cells usually have a single circular chromosome not enclosed in a nuclear membrane.

Question 2

A microbiologist isolates a bacterium with a thick peptidoglycan layer, teichoic acids, and no outer membrane. Which Gram stain result and antibiotic susceptibility would you expect?

Accepted Answer

Gram-positive; susceptible to penicillin

Question 3

Which structure allows bacteria such as Neisseria gonorrhoeae to adhere to human tissues and is also involved in biofilm formation?

Accepted Answer

Fimbriae

Question 4

A patient is infected with a bacterium that survives phagocytosis and forms biofilms on medical devices. Which structure most likely contributes to both of these abilities?

Accepted Answer

Glycocalyx (capsule)

Question 5

Which of the following best describes the function of the bacterial cell wall?

Accepted Answer

It prevents osmotic lysis and protects the plasma membrane.

Question 6

A bacterium is placed in a hypertonic solution. Predict what will happen to the cell and explain the process using osmosis.

Accepted Answer

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

Question 7

Which of the following is a correct description of the Gram stain mechanism for Gram-positive bacteria?

Accepted Answer

Alcohol dehydrates the thick peptidoglycan, trapping crystal violet-iodine complexes inside the cell.

Question 8

Which of the following best explains why Mycobacterium species are acid-fast?

Accepted Answer

Their cell walls contain mycolic acids that retain carbolfuchsin even after acid-alcohol wash.

Question 9

Which of the following is true regarding bacterial endospores?

Accepted Answer

They are resistant to desiccation, heat, and chemicals, and can survive for thousands of years.

Question 10

A scientist discovers a bacterium with a single circular chromosome, no histones, and division by binary fission. Which domain does this organism most likely belong to?

Accepted Answer

Bacteria

Question 11

Which of the following best describes the function of porins in Gram-negative bacteria?

Accepted Answer

They form channels through the outer membrane for the passage of molecules.

Question 12

Which of the following is a correct match between bacterial shape and arrangement?

Accepted Answer

Staphylococci: clusters of spherical cells

Question 13

Which of the following antibiotics specifically interferes with the formation of peptide bridges in peptidoglycan?

Accepted Answer

Penicillin

Question 14

A bacterium is found to have endoflagella anchored at one end, causing it to move in a corkscrew fashion. Which type of bacterium is this?

Accepted Answer

Spirochete

Question 15

Which of the following best describes facilitated diffusion in bacterial cells?

Accepted Answer

Movement of solutes from high to low concentration through membrane proteins, without energy expenditure.

Question 16

Which of the following is a function of the bacterial cytoskeleton?

Accepted Answer

Cell division and maintaining cell shape

Question 17

A bacterial cell is exposed to lysozyme. Which of the following best explains the effect on the cell wall?

Accepted Answer

Lysozyme hydrolyzes bonds in the glycan portion of peptidoglycan, weakening the cell wall.

Question 18

Which of the following inclusions would you expect to find in a photosynthetic bacterium for carbon fixation?

Accepted Answer

Carboxysomes

Question 19

Which of the following best describes the plasma membrane according to the fluid mosaic model?

Accepted Answer

A viscous, self-sealing bilayer where proteins and phospholipids move freely.

Question 20

A bacterium lacking a cell wall is placed in distilled water. Predict the outcome and explain using the concept of osmosis.

Accepted Answer

The cell will swell and may lyse due to water entering by osmosis.

Functional Anatomy of Prokaryotic and Eukaryotic Cells

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