Foundation

Question 1

All spore forming bacteria are..

Answer 1

gram positive

Question 2

What feature of bacterial cell wall is unique to bacteria? What is its structure

Answer 2

Peptidoglycan Joined in 2 directions

• across = alternating sugar subunits
• down - peptide chains to..
  
  • pentapeptide bridges

Question 3

Features of gram positive cell walls

Answer 3

• no outer membrane - thick peptidoglycan - teichoic acids (PAMP)

Question 4

Features of gram negative cell walls

Answer 4

• outer membrane (then periplasmic space)
• with LPS
• thinner cell wall

Question 5

Outer membrane in gram negative bacteria

• what is its function
• what is it stabilised by?

Answer 5

Function: relatively impervious

• prevent entry of bile salts etc
• has protein channels - small molecules can get through
• has specific carriers for lager molecules

Stabilised by LPS = endotoxin

• takes the palce of a phospholipid in the membrane
• repeating units of O antigen on extracellular surface

Question 6

Acid fast bacteria features

Answer 6

• thick, waxy wall
• peptidoglycan base layer + some additional layer
• lipid ruch, but no outer membrane

resistance to drying, chemicals, antibiotics

slows its nutrient uptake

Question 7

Bacterial capsules

• what are they usually made of?
• which bacteria has an unusual capsule?
• function

Answer 7

Usually made of polysaccharide material

Bacillus anthracis - has a polypeptide capsule (is G+ rod)

Function:

• resist dehydration
• contribute to virulence
• protect against phagocytosis

Question 8

What are the stages of bacterial pathogenesis?

Answer 8

Adherence

Entry of host

Overcoming phagocytosis

Overcoming adaptive immunity

Production of tissue damage