Question 1

Which of the following statements best describes the main structural difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have internal membrane-bound organelles, while prokaryotic cells do not.

Question 2

A patient presents with a severe dental infection. Microscopy reveals bacteria embedded in a sticky matrix on the tooth surface. Which bacterial structure is most responsible for this biofilm formation?

Accepted Answer

Capsule (glycocalyx)

Question 3

Which of the following is a function of the bacterial cell wall?

Accepted Answer

Protection from osmotic forces

Question 4

Gram-negative bacteria are more resistant to antibiotics than Gram-positive bacteria primarily because:

Accepted Answer

Their outer membrane contains lipopolysaccharide (LPS), which acts as a barrier.

Question 5

Which equation best represents the osmotic pressure ($$\Pi) $$across a semipermeable membrane?

Accepted Answer

$$\Pi = iMRT$$

Question 6

A bacterium moves toward a nutrient source. Which term describes this movement, and what is the mechanism?

Accepted Answer

Chemotaxis; flagellar rotation in a series of runs and tumbles

Question 7

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

Accepted Answer

Facilitating DNA replication

Question 8

Which bacterial structure is directly involved in the transfer of genetic material between cells?

Accepted Answer

Conjugation pilus

Question 9

A Gram-positive bacterium is exposed to a hypertonic solution. What will happen to the cell?

Accepted Answer

The cell will shrink as water leaves, but the cell wall prevents complete collapse.

Question 10

Which of the following is a unique feature of Gram-negative bacteria?

Accepted Answer

Presence of lipopolysaccharide (LPS) in the outer membrane

Question 11

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

Accepted Answer

Group translocation

Question 12

Which of the following bacteria is most likely to survive extreme environmental conditions such as heat and radiation?

Accepted Answer

Bacteria forming endospores

Question 13

Which of the following is true about bacterial ribosomes?

Accepted Answer

They are the site of protein synthesis.

Question 14

Which of the following best describes the arrangement of phospholipids in a bacterial cytoplasmic membrane?

Accepted Answer

Phospholipids form a bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.

Question 15

Which bacterial structure is most important for motility and movement toward favorable conditions?

Accepted Answer

Flagella

Question 16

Which of the following is a consequence of biofilm formation on medical devices?

Accepted Answer

Biofilms increase antibiotic resistance.

Question 17

Which of the following equations represents the relationship between concentration gradient and diffusion rate?

Accepted Answer

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

Question 18

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

Accepted Answer

Protein synthesis

Question 19

Which of the following is true about endoflagella in spirochetes?

Accepted Answer

They wrap around the cell between the cell membrane and outer membrane, causing corkscrew motility.

Question 20

Which of the following bacteria lacks a cell wall and is therefore resistant to antibiotics targeting peptidoglycan?

Accepted Answer

Mycoplasma

Cell Structure and Function in Microbiology

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