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
what two elements make up LPS
¡hola!
O antigen and lipid A
LPS stands for, and is also called
lipopolysaccharide. endotoxin
name an example of a bacteria that lack a cell wall
mycoplasma species
what shape do mycoplasma species take?
pleomorphic
what provides rigidity in mycoplasma? where are they located?
sterols in the cytoplasmic membrane
what staining is used in mycobacteria? why?
acid fast. no cell wall!
what are three special facts about archaeal cell walls?
- variety of cell wall types
- no peptidoglycan
- have an S layer (some bacteria have an S layer too)
cell membrane aka
cytoplasmic membrane
cytoplasmic membrane aka
cell membrane
what is the role of the cell membrane? (4)
- selective permeability
- transporters
- carriers
- structural and sensor proteins are embedded in the cell membrane
what is the role of the cytoplasmic membrane? (4)
Carrie transports her professional perm
- selective permeability
- transporters
- carriers
- structural and sensor proteins are embedded in the cell membrane
what two general transport systems direct movement of molecules across the cytoplasmic membrane?
- facilitated diffusion
- active transport
describe facilitated diffusion
No energy expended, goes with the concentration gradient
describe active transport
energy expended (against concentration gradient)
list one famous example of active transport?
efflux pump
what do efflux pumps do?
what type of transport system do they represent?
active transport, use energy, pump antibiotics out of the cell
which secretion system have we studied so far in class?
type III
Type III secretion system aka
injectisome
Injectisome aka
Type III secretory system
what is the role of T3SS?
in other words, what is it important for and how?
important for virulence by causing changes in the host cell
what happens if alcohol is not used for long enough during a gram stain?
G- does not lose CV and looks purple
what happens if alcohol is used for too long during a gram stain?
peptidoglycan in G+ dries out and cracks, so the G+ loses its purple color
