Bacteria Flashcards
What is Bacteria
Ubiquitous
Prokaryotes
lack of membrane-bound organelles
Circular chromosome
Cell shapes
determined by cell wall
Coccus,coccobacillus,vibrio,bacillus,spirullam,spirochete
Gram-positive=spherical
Gram=negative=more rod shape
Cell arrangment
Number and pattern of bacteria attached after cell division
single=one,Diplo=pair,Tetrad=four,square
Sarcina=eight,cube,Staphylo=cluster
Strepto=sheets, chains,Palisade-fence-like
Cell membrane
Ester bond
Bilayer
Hopanoids
Cell wall function
Determines +maintains shape
Peptidoglycan cell wall
direct contact
inhibit entry of certain molecules
protection from osmotic pressure
Gram positive
Thick PGL
Teichoic +lipoteichoic acids
attachment + different among G+
G- Outer membrane
selectively permeable
structural integrity
Porins-channels
Lipids, lipoproteins,LPS
Lipid A-endotoxin
O antigen
Gram-negative
Thin PGL
no teichoic acids
periplasmic space
outer membrane
Mycobacteria
Thin PGL
Mycomembrane-mycolic acid layer,porins,single cytoplasmic membrane
Mycoplasma
No cell wall
Lipoprotein membrane
intracellular parasite
Resistant to several antibotics
Gram staining
Stain the PGL
Determine if the bacteria are gram + or gram _
Crystal violet-all cells purple, Iodine-all cells darker purple, Ethanol decolorizer-breaks complex apart, Safranion-counterstain all cells
Gram stain anomalies
Over-decolorization-all cells pink
under-decolorization-all cells purple
Old G+ cells have leaky walls-stains don’t stick
Acid-fast stain
Mycobacteria-gram insensitive,Waxy substance
Fuchsia-lipid soluble dye
Decolorizer-acid alcohol
Methylene-counterstain
Pink
