W2/L4 & W2/L7 Flashcards
(19 cards)
What colour does a gram +’ve cell wall go?
Purple
What colour does a gram -‘ve cell wall go?
Pink
What is the structure of a gram +’ve cell wall?
from outside to inside
Thick peptidoglycan
(space)
Plasma membrane
What is the structure of a gram -ve cell wall?
from outside to inside
Outer membrane (space) Think peptidoglycan (space) Plasma (/inner) membrane
The walls of which cells contain teichoic acid?
Gram +’ve
What’s the role of the outer membrane of Gram -ve bacteria?
Prevents entry of bile sals and some Ab’s
What molecule stabilises the outer membrane of Gram -‘ve bacteria?
LPS
What is the periplasmic space and in which bacteria is it found?
The space between the outer & inner membrane of Gram -‘ve bacteria
Includes the thin peptidoglycan layer.
What’s the structure of LPS?
Lipid A
attached to a core polysaccharide
with repeating units of O-antigen attached.
What does LPS stand for?
Lipopolysaccharide
What’t the benefit of being an acid-fast bacteria?
Resistant to:
Drying
Harsh chemicals
ABs
What’s the disadvantage of being an acid-fast bacteria?
Slow nutrient uptake means slow growth
How thick is the peptidoglycan of a gram +’ve cell wall?
15-80 nm
How thick is the peptidoglycan of a gram -‘ve cell wall?
10 nm
Why are the gram +’ve cells purple?
They retain the crystal violet dye
What is the capsule usually made of?
Polysaccharide
What method do you use to visualise a capsule in LM?
Negative staining
What’s the benefit to being an encapsulated bacteria? (3)
Protection against dehydration
Protection from p’cytosis
Contribution to virulence
What genus of bacteria are known for making spores?
Clostridium
