Question 1

Which of the following statements correctly describes a major difference between the two prokaryotic domains, Bacteria and Archaea?

Accepted Answer

Archaea have unique membrane lipids with ether linkages, while Bacteria have ester-linked membrane lipids.

Question 2

Which of the following is an extracellular structure commonly found in prokaryotes and is involved in attachment to surfaces?

Accepted Answer

Pilus (Fimbriae)

Question 3

What is the average diameter of a typical prokaryotic cell?

Accepted Answer

$$0.5-5\ \mu m$$

Question 4

Gram-positive and Gram-negative bacteria differ in their cell envelope structure. Which feature is unique to Gram-negative bacteria?

Accepted Answer

Outer membrane containing lipopolysaccharide (LPS)

Question 5

A scientist stains two bacterial samples: one turns purple, the other pink. What does this indicate about their cell wall structure?

Accepted Answer

Purple indicates Gram-positive, which has a thick peptidoglycan layer.

Question 6

Which of the following best describes passive transport in prokaryotic cells?

Accepted Answer

Movement of substances down their concentration gradient without energy input.

Question 7

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

Accepted Answer

The cell will lose water and shrink (plasmolysis).

Question 8

Which structure is primarily responsible for bacterial motility?

Accepted Answer

Flagella

Question 9

How do periplasmic flagella benefit spirochetes in terms of movement and survival?

Accepted Answer

They enable corkscrew motion, facilitating movement through viscous environments.

Question 10

In prokaryotes, how is the nucleoid region different from the nucleus of eukaryotic cells?

Accepted Answer

The nucleoid is not membrane-bound and contains a single circular chromosome.

Question 11

Which of the following best explains how DNA replication is coordinated with cell growth and division in prokaryotes?

Accepted Answer

DNA replication and cell division are tightly linked, often overlapping to allow rapid growth.

Question 12

Which function is associated with thylakoids in prokaryotic cells?

Accepted Answer

Photosynthesis

Question 13

What is the primary role of bacterial endospores?

Accepted Answer

Enable survival in harsh environmental conditions

Question 14

Which of the following bacteria is known to cause disease in humans through endospore formation?

Accepted Answer

Bacillus anthracis

Question 15

Why are antibiotics that target peptidoglycan synthesis generally ineffective against human cells?

Accepted Answer

Human cells lack peptidoglycan in their cell walls.

Question 16

Which antibiotic mechanism specifically targets bacterial ribosomes, inhibiting protein synthesis?

Accepted Answer

Tetracycline binding to the 30S ribosomal subunit

Question 17

A patient is infected with a Gram-negative bacterium. Which structural feature makes this bacterium more resistant to certain antibiotics?

Accepted Answer

Presence of an outer membrane with lipopolysaccharide

Question 18

Which of the following equations best represents the osmotic pressure ($$\Pi) $$across a bacterial cell membrane?

Accepted Answer

$$\Pi = CRT$$

Question 19

A Gram-positive bacterium is exposed to lysozyme. What is the most likely effect?

Accepted Answer

Lysozyme will break down peptidoglycan, compromising cell wall integrity.

Question 20

Which of the following best explains why Gram-negative bacteria are more susceptible to drying out than Gram-positive bacteria?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer that retains moisture.

Prokaryotic Cell Structure and Function: Study Notes for Microbiology

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