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27 Cards in this Set

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describe the 4 primary componenets of a bacterial cell and their function
1. capsule-prevents uptake; anti-phagocytic
2. ribosomes-dry weight-50% ribsomes
3. cytoplasmic inclusions-
4. DNA is coiled into a neculoid or plasmid*
5. double helix DNA structure
General componenets of a bacterial cell wall-
rod shaped; e-coli
gram + fimbraie
gram - pilli
1-3 microns
Outer membrane plays a role in SHOCK-endotoxin-->lipopolysaccharide
4 features of cytoplasm
1. site of metabolic act
2. packed w/ribsomes (30s+50s=70s); that are smaller than in e cells-targets bacteria; (s-->sedentation
3. most exist as polysomes..grops of ribsomes
4.inclusion bodies..storeage granuls and gas vacuolues
5 features of cell wall
1. peptidoglycan, murein layer-w/o this orga will burst
2. absent in eukarytoes
3. deinite struture; NAM and NAG give shape
4. provides shape and strenght
5. murein layer is unique to bacteria
a. site for lysozyme-can cut murein layer
b. site for many antibotics: pencillin, cephalopsoins, vancoymocin
*drugs target this layer b/c not in humans
Gram stainig
differentiates bw large peptidocyclan layer:
1. gram + has petpidocylan layer--purple
2. gram - thin peptidoglycan layer-pink stain (lipid A is a strong immunogen)
3. cystal violet-penetrates both types of bacteria-after EtOH wash, counterstain w/saffrini, pink stains negative
cytoplasmic membrane
"prom"
serves as the osmotic barrier
1. invovled in specific transport
2. site of respiration
3. highly metabolic
4. composed of phospholipids (hydrophilic head and tail) & protein (transport nuts across the membrane, generates ATP, and senses environemtn change)
Nucleoid
single closed cirucle of ds DNA and is convouluted with foldings; NOT enclosed by membrane(maybe reason why bacteria replicate so quickly)
plasmid
smaller circles of DNA that ofen carry genes for antibotic resistance or toxin production (other virulence factors)-important in genetic exchange
outer wall
in gram - ONLY; have outer membrane in addition to peptidoglcayn (thin)
1. protects cell from toxic material and froms the periplams which contains adigestistive NZs
2. proins-allow entry of nut moleucles into periplasm-broken down-gets into cell
3. lipopolysaccharide--endotoxin
a. o-specififc side chain-made of CHO
b. lipid A-most virulent portion
c. fatty chain acids
3 features of the envelope
a. anything o/side cytoplasm
b. w/capsule: virulent (S)
c. w/o capsule avirulent (R)
3 more features of envelope
d. gram neg vs. gram +
e. mycoplasma-no PG layer-so cytoplasmic membrane only
f. capsule=glycolcalyx(exopolysaccharide)(exopolysaccharide):
Gram negative bacteria
1. capsules
2. outer membranes
3. their murein layer is thin
4. cytoplasmic membranes
Gram positive bacteria
1. capsules (slime layer)
2. a think murien layer
3. cytoplasmic membranes
Mycoplasmsa
lack a cell wall-they have cytoplamsic membranes only
3 features of the capsule
--made of glycoclayxx (exopolysaccharide)
1. viscouse, fibrous, matrix that is antigpahgocytic
2. encapsulated strains are referred to as smooth (S)
3. noneencapsulated strains are rough (R)
appendages:
Outer portion of bacterial cell: include Pili (-) or fimbraie (+)
and
flagella
Pili - or fimbriae +(interchangeable terms) types
2 types:
a. common type-used for adhesion/attachment
b. sex type-involved in genetic transfer: ex-in E-coli
Flagella
provides motility, driven by pmf, consists of long helical filament, flexible hook, and a basal body-sitff area that rotates quickly counterclockwise
a. turns at speeds up to 1000rpm (counterclockwise)
b. provides chemotaxis to cells
c. senses environemnt-swims tward good
5 features of prokarytos (see chart in printed out objs on gold CD)
1. bacteria are prokarytotes-relatively small
2. no nuclear membrane
3. cytoplams rich in ribosomes
4. have plasmids
metabolize and grow so fast bc they're small: grow 10-100 times faster:s ome can double in 20 secs
4 features of eukarytoes:
1. everything (aside from prokarytoes) and are 10-100 times larger
2. nuclear membrane is present
3. ribosomes are on rER
4. usually plasmids are absent, but some DNA is in mitochondria
5. clockswise-they tumble
desribe the humna-pathogen dynamic
if there is a lot of pathogenicity-bacteria are favored and host defenses fight bacteria
inflammatory response in Gram - and gram +
so sepsis in both
What provides entry of nutrient molecules into gram-negative moldues?
porins
3 types of human-bacterial interactions
1. mutualism-a mutually beneficial assoication (some normal flora)
2. commensalism: one org mya benefit but neighter is harmed (most normal flora)
3. pariasititism: one org lives at the expense of the other and may do harm (pathogen)
Invasivness involves what 3 factors:
1. colonization
2. ability to bypass or overcome host defesnes
3. production of extracellular substances which faciliate invasion
Toxigenesi
1. soluble
2. transported by blood/or lymph
3. cause cytotoxic effects at tissue sites
Classification of bacteria based off of what 3 things:
1. morphology size
2. gram stain or other diff stain such as acid fast stain
3. specific antigens, biocemcal epxression or gentic makeup