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27 Cards in this Set
- Front
- Back
describe the 4 primary componenets of a bacterial cell and their function
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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 |
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General componenets of a bacterial cell wall-
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rod shaped; e-coli
gram + fimbraie gram - pilli 1-3 microns Outer membrane plays a role in SHOCK-endotoxin-->lipopolysaccharide |
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4 features of cytoplasm
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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 |
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5 features of cell wall
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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 |
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Gram stainig
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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 |
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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) |
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Nucleoid
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single closed cirucle of ds DNA and is convouluted with foldings; NOT enclosed by membrane(maybe reason why bacteria replicate so quickly)
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plasmid
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smaller circles of DNA that ofen carry genes for antibotic resistance or toxin production (other virulence factors)-important in genetic exchange
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outer wall
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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 |
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3 features of the envelope
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a. anything o/side cytoplasm
b. w/capsule: virulent (S) c. w/o capsule avirulent (R) |
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3 more features of envelope
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d. gram neg vs. gram +
e. mycoplasma-no PG layer-so cytoplasmic membrane only f. capsule=glycolcalyx(exopolysaccharide)(exopolysaccharide): |
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Gram negative bacteria
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1. capsules
2. outer membranes 3. their murein layer is thin 4. cytoplasmic membranes |
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Gram positive bacteria
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1. capsules (slime layer)
2. a think murien layer 3. cytoplasmic membranes |
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Mycoplasmsa
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lack a cell wall-they have cytoplamsic membranes only
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3 features of the capsule
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--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) |
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appendages:
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Outer portion of bacterial cell: include Pili (-) or fimbraie (+)
and flagella |
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Pili - or fimbriae +(interchangeable terms) types
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2 types:
a. common type-used for adhesion/attachment b. sex type-involved in genetic transfer: ex-in E-coli |
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Flagella
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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 |
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5 features of prokarytos (see chart in printed out objs on gold CD)
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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 |
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4 features of eukarytoes:
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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 |
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desribe the humna-pathogen dynamic
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if there is a lot of pathogenicity-bacteria are favored and host defenses fight bacteria
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inflammatory response in Gram - and gram +
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so sepsis in both
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What provides entry of nutrient molecules into gram-negative moldues?
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porins
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3 types of human-bacterial interactions
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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) |
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Invasivness involves what 3 factors:
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1. colonization
2. ability to bypass or overcome host defesnes 3. production of extracellular substances which faciliate invasion |
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Toxigenesi
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1. soluble
2. transported by blood/or lymph 3. cause cytotoxic effects at tissue sites |
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Classification of bacteria based off of what 3 things:
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1. morphology size
2. gram stain or other diff stain such as acid fast stain 3. specific antigens, biocemcal epxression or gentic makeup |