Functional anatomy of Prokaryotic and Eukaryotic cells

Question 1

What are the main functions of the cell wall?

Answer 1

Prevents cell lysis, helps maintain cell shape, point of anchorage for flagella

Question 2

What is the primary component of the bacterial cell wall?

Answer 2

Peptidoglycan

Question 3

What are the two main types of bacterial cell walls?

Answer 3

Gram-positive and Gram-negative

Question 4

Describe the structure of Gram-positive cell walls.

Answer 4

Thick peptidoglycan layer

Teichoic acid links the sheet layers of peptidoglycan together.

Lipoteichoic acid links peptidoglycan to the plasma membrane.

Question 5

Describe the structure of Gram-negative cell walls.

Answer 5

Outer membrane
-lipopolysaccharide (endotoxin)
- Periplasm
- Porins: channel protein that allows transport throught the membrane.
Thin layer of peptidoglycan

Question 6

Is the Gram stain a simple stain or a differential stain?

Answer 6

Differential stain

Question 7

What reagent is used first in the Gram staining process?

Answer 7

Crystal violet

Question 8

What is the role of iodine in the Gram stain mechanism?

Answer 8

A mordant
Forms crystals with crystal violet (CV-I complexes) that are too large to diffuse across the gram-positive cell wall.

Question 9

What effect does alcohol have during the Gram staining process on Gram-positive bacteria?

Answer 9

Dehydrates peptidoglycan, making it more impermeable

Question 10

What effect does alcohol have during the Gram staining process on Gram-negative bacteria?

Answer 10

Dissolves outer membrane and creates holes in the thin peptidoglycan layer

Question 11

What is an example of atypical cell walls?

Answer 11

Acid-fast bacteria (Mycobacterium and Nocardia)

Question 12

What is osmotic lysis?

Answer 12

The bursting of a cell due to excessive water intake

In a hypotonic solution

Question 13

What is plasmolysis?

Answer 13

The shrinking of a cell due to loss of water

In a hypertonic solution

Question 14

What are the three types of osmotic solutions?

Answer 14

• Isotonic solution
• Hypotonic solution
• Hypertonic solution

Question 15

What is the medical significance of peptidoglycan?

Answer 15

Unique to bacteria, it is a target of some antibiotics and recognized by the innate immune system

Question 16

What are teichoic acids?

Answer 16

Components of Gram-positive cell walls that link peptidoglycan layers together

Question 17

What is the primary function of fimbriae in prokaryotic cells?

Answer 17

Allow attachment to surfaces and other cells

Question 18

What is the difference between prokaryotic and eukaryotic cells regarding chromosomes?

Answer 18

Prokaryotes have one circular chromosome, not in a membrane; eukaryotes have paired chromosomes in a nuclear membrane

Question 19

What are the common bacterial morphologies?

Answer 19

• Coccus (spherical)
• Bacillus (rod-shaped)
• Coccobacillus (short, fat bacillus)
• Spiral (curved)

Question 20

What are the common bacterial arrangements?

Answer 20

• Diplo- (pairs)
• Strepto- (chains)
• Staphylo- (clusters)
• No arrangement (random)

Question 21

What is the role of capsules in prokaryotic cells?

Answer 21

Aid in attachment and impair phagocytosis

Question 22

What is the main function of flagella in prokaryotic cells?

Answer 22

Enable motility

Question 23

What is the significance of the periplasm in Gram-negative bacteria?

Answer 23

Contains peptidoglycan, degradative enzymes, and toxins

Question 24

What are the main functions of mitochondria and chloroplasts in eukaryotic cells?

Answer 24

Energy conversion reactions; mitochondria for cellular respiration and chloroplasts for photosynthesis

Question 25

What is selective permeability in the plasma membrane?

Answer 25

Allows passage of select molecules while restricting others

Question 26

What are the types of passive transport across membranes?

Answer 26

Simple diffusion Facilitated diffusion Osmosis

Question 27

What does the endosymbiotic theory explain?

Answer 27

The evolution of eukaryotic cells' organelles from prokaryotes.

Question 28

What is the structure of prokaryotic ribosomes compared to eukaryotic ribosomes?

Answer 28

Different in structure, prokaryotic ribosomes are 70S A small subunit: 20s A large subunit: 50s Complete unit: 70s.

Question 29

What are plasmids?

Answer 29

Small, circular, extrachromosomal DNA in prokaryotic cells

Question 30

What is sporulation?

Answer 30

Endospore formation Triggered by nutrient deficiency of key nutrients.

Question 31

What is germination?

Answer 31

Return vegetative (active) state. Triggered by physical or chemical damage to the endospore's coat. Can also be triggered by nutrient availability.

Question 32

What is the role of lysozyme in relation to peptidoglycan?

Answer 32

Attacks disaccharide bonds in peptidoglycan. Causing damage to the cell wall. Bacteria with weakened cell walls are susceptible to osmotic lysis.

Question 33

What is the effect of penicillin on bacterial cell walls?

Answer 33

Inhibits peptide cross-bridge formation in peptidoglycan

Question 34

What is active transport in prokaryotic cells?

Answer 34

Movement of solutes against their concentration gradient requiring energy

Question 35

Define simple diffusion

Answer 35

Movement of a solute from an area of high concentration to an area of low concentration.

Question 36

Facilitated diffusion

Answer 36

Solute relies on a transporter protein in order to move down its gradient.

Question 37

Define Osmosis

Answer 37

Diffusion of water down its gradient.