1.02 - The Bacterial Cell

Question 1

Describe Difference between Prokaryotic and Eukaryotic Cells.
Nucleus
Membrane Bound Organelles
Cell Wall
Cytoskeleton
Chromosome
Cell Division

Answer 1

Prokaryotic
Nucleus: Absent
Membrane Bound Organelles: Absent
Cell Wall: Present, Chemically Complex
Cytoskeleton: Absent
Chromosome: Single, Circular
Cell Division: Binary Fission

Eukaryotic
Nucleus: Present
Membrane Bound Organelles: Present (e.g. mitochondria)
Cell Wall: Chemically simple when present
Cytoskeleton: Present
Chromosome: Multiple chromosome
Cell Division: Involves Mitosis

Question 2

How do bacterial cells divide?

Answer 2

Binary Fission

Question 3

What are the phases of Bacterial Replication?

Answer 3

1. Lag Phase
2. Exponential (log) Phase
3. Stationary Phase
4. Death Phase

Question 4

What are some basic classification classes for bacteria?

Answer 4

Oxygen utilisation capability
Temperature
pH

Question 5

Aerobe

Answer 5

A bacterium that requires oxygen to function/replicate

Question 6

Anaerobe

Answer 6

A bacterium that does not require oxygen to function/replicate

Question 7

Facultative Anaerobe

Answer 7

A bacterium that can grow in the presence or absence of oxygen.
Encompasses most medically relevant bacteria.

Question 8

What are the three stages of bacterial translation?

Answer 8

Initiation
Elongation
Termination

Question 9

Define: Species

Answer 9

A species is defined as a collection of strains that sure many stable properties and differ from other groups of strains

Question 10

What properties are used to identify bacteria at the species level?

Answer 10

Morphology - colonial cellular
Physiology
Metabolic Activities
Ecological Characteristics

Question 11

What do Bacterial Transpeptidases do?

Answer 11

Catalyse the cross linking of peptidoglycan units in the bacterial cell wall

Question 12

What class of drugs inhibit Bacterial Transpeptidases

Answer 12

Beta-lactams such as penicillin

Question 13

What does the bacterial cell wall play a role in?

Answer 13

Identification - gram stain
Virulence - adherence and gaining entry
Interacting with the immune system
Antibiotic targets

Question 14

What are the steps in a gram stain?

Answer 14

1. Crystal Violet (stains peptidoglycan purple)
2. Gram’s Iodine (binds to crystal violet and traps it in the cell)
3. Decoloriser (Alcohol/Acetone) (removes crystal violet in gram negative bacteria)
4. Safranin Red (Counterstains gram negative bacteria)

Question 15

What colour are gram positive bacteria after a gram stain?

Answer 15

Purple

Question 16

What colour are gram negative bacteria after a gram stain?

Answer 16

Red/Pink

Question 17

What two subunits make up Peptidoglycan?

Answer 17

NAG & NAM

Question 18

What parts of the envelope are unique to gram positive bacteria?

Answer 18

Techoic Acid

Lipotechoic Acid

Question 19

What layer of the envelope is unique to gram negative bacteria?

Answer 19

The Outer Membrane

Question 20

What is often found in the outer membrane of only gram negative bacteria?

Answer 20

Lipopolysaccharide

Question 21

What are the components of lipopolysaccharide?

Answer 21

O-Antigen

Lipid A

Question 22

What are capsules composed of?

Answer 22

Repeating polysaccharide units

Question 23

What type of virulence factor are capsules?

Answer 23

Impedins. Resistance to an important innate immune function such as phagocytosis