Mid Term 1 Review Questions (Part 2.1) Flashcards
light vs. electron microscopy
LIGHT: uses light and lenses. magnifies 1000x. cell size, shape, and MOTILITY.
ELECTRON: uses electrons, not light, 100,000x magnification. can’t see living things.
what does pleomorphic mean?
varying in shape
what does monomorphic mean?
one form or shape
what is a capsule?
what is it also called?
what is it made of?
outer layer of prokaryotic cell. glycocalyx. shell of sugars.
what role does a capsule play in pathogenesis?
waves HAEEE
helps pathogens
1. HIDE
2. ADHERE
3. ESCAPE PHAGOCYTOSIS
how can we identify capsulated bacteria? (2)
1.they form shiny slimy colonies on solid media
2. stains
what is the purpose of the cell wall? (2)
- provide rigidity to the cell
- keep it from bursting
describe the location of the bacterial cell wall
capsule surrounds cell wall surround cytoplasmic membrane
name two places where lysozyme can be found
tears, egg whites
what is the medical significance of the bacterial cell wall? (3)
SLIT
- target for selective toxicity (targeted by certain antibiotics)
- target of lysozyme
- recognized by the innate immune system (it’s a PAMP, MAMP)
what are the steps of gram staining?
- CV: both cells turn purple.
- Iodine: CV sticks to G+, nothing happens to G-. CV is present but can be easily washed away by…
- Alcohol: CV is trapped in G+, punctures outer membrane of G-, CV washes away. most important step and easiest to mess up.
- Safranin: stains G- pink.
In the name E. coli O157:H7, what does the O indicate?
O antigen in G- cell wall
In the name E. coli O157:H7, what does the H indicate?
presence of flagella
describe a G+ bacterial cell wall (4)
- thick layer of peptidoglycan (PAMP)
- teichoic acids
- gel-like material
- cytoplasmic membrane
describe a G- bacterial cell wall (5)
- LPS (O antigen, lipid A) (ENDOTOXIN)
- Outer membrane (lipid bilayer) (porins)
- Periplasm
- Thin layer of peptidoglycan
- Cytoplasmic membrane