Bacteriology Flashcards
What are the three components of a gram positive bacteria’s cell wall?
- Teichoic acid
- Peptidoglycan
- Plasma membrane
What are the five components of a gram negative bacteria’s cell wall?
- Lipopolysaccharide
- Phospholipid
- Lipoprotein
- Peptidoglycan
- Plasma membrane
Peptidoglycans contain… held together by…
repeating units of sugars held together by peptide chains
All gram+ cell walls contain…
teichoic acid
Where can teichoic acid be found?
Gram+ cells
Which type of bacteria will stain pink?
Which will stain purple?
Gram- stains pink
Gram+ stains purple
Teichoic acid protrudes above the cell wall, what is the effect?
A negative charge is imparted to the cell
Stains have a ___ charge, allowing for stronger bonding with cells with a ___ charge.
Stains have a negative charge, allowing for stronger bonding with cells with a positive charge.
Which feature of a gram+ cell wall is required for infection by streptococcus spp only?
M protein
How does M protein function in a gram+ cell wall?
Protrudes from cell wall making cell too large to phagocytize
Is M protein likely to mutate?
Yes, highly susceptible to mutation
Mycolic acid in a gram+ cell wall is found only in…
Mycobacterium spp
What is the structure and function of mycolic acid in a gram+ cell wall?
Waxy lipid inside cell wall structure that acts as a barrier against antibiotics and host defenses
What is the unique outer layer of a gram- cell wall?
Lipopolysaccharide
Beneath the outer membrane of a gram- cell wall lies…
a thin layer of peptidoglycan
What is the role of lipid A in a gram- cell wall?
Endotoxin that is released when cell dies
O Polysaccharides are part of…
lipopolysaccharides of the outer layer of gram- cell wall
What is the function of the O polysaccharide portion of a lipopolysaccharide?
Used as a diagnostic marker by the gram- cell
What is the primary stain of Gram stain?
Crystal violet
What is the mordant of Gram stain?
Gram’s iodide
What is the decolorizer of Gram stain?
95% ethanol
What is the secondary stain of Gram stain?
Safranin
What is the function of Gram’s iodide as a mordant in Gram stain?
Fixes dye to the material (cells, tissue, etc)
Glycocalyx consists of…
a capsule and slime layer