Shared Flashcard Set

Details

Bacterial Structure, Genetics, etc.
Micro - Fundamentals
14
Medical
Graduate
08/20/2012

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Cards

Term
Peptidoglycan
Definition
only in bacteria, layers of polysaccharide chains linked by short peptides, N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG). In Gram pos PG is cross linked by peptide bonds. Lysozyme cleaves PG.
Term
Outer membrane
Definition
Gram neg only. Barrier to host enzymes and some antibiotics, contains many proteins such as porins, readily exposed to host.
Term
Lipopolysaccharide (Endotoxin)
Definition
Major mediator of inflammation/fever for Gram neg. Three units: lipid A (toxic) core polysacc, O-antigen polysacc side chains.
Term
Teichoic Acid
Definition
Polymers of glycerol phosphate or ribitol phosphate in outer layer of Gram pos cell wall. Two types: wall TA and lipoteichoic TA.
Term
Bacterial Cell Membrane
Definition
Lack sterols, functions in electron transport (no mitochondria)
Term
Flagella
Definition
Composed of flagellin, flagellar antigens are used to identify different strains. Cocci do not have flagella. Number/location of flagella varies with species.
Term
Capsule
Definition
Gelatinous covering composed of polysacc. except B. anthracis. Small antigenic differences distinguish serotypes/serogroups. Virulence factor that inhibits phagocytosis and complement.
Term
Pili/Fimbrae
Definition
Short filaments composed of pilin, mediate attachment and transfer of DNA. Adhesin at tip. Specialized sex pilus attaches male to female. Pili can be retracted to bring bacterium closer to attached target.
Term
Spores/Endospores
Definition
Some genera stop growth and produce spores when conditions are not optimal, resist drying, heat, radiation and chemicals. When conditions improve spores germinate. Some spores, such as with B. anthracis, are the infectious form.
Term
Gram positive bacterial traits
Definition
Thick, cross-linked PG, no LPS, no outer membrane (or periplamic space), no porins, have TA, WTA, LTA.
Term
Gram negative bacterial traits
Definition
Thin PG with less cross links, LPS is major component of outside of outer membrane, have periplasm, have porins, do not form spores.
Term
Transformation
Definition
Lysis of cell, DNA taken up by another bacterium.
Term
Transfection
Definition
Phage obtains some bacterial DNA and transmits it to another host.
Term
Conjugation
Definition
Free or integrated plasmid or even regular DNA moves through sex pilus to another organism.
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