Bacteria Cell Sturcture

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1.Microbiology
Mmicroscope
Iindependent unit
Ccomparatively less complex
Rrapid rate of reproduction
Oomnipresent
humans are living repositories of bacteria/microbes
borne sterile
microbe on all surface area of the body
sterile areas: eyes, brain, spinal cord, bones, kidney, internal organs
mutualistic relationship: we provide site and nutrient and microbes provide vitamin, aid in food digestion
division of microbial world
living component: organism
prokaryotic
nucleoid area
one circular chromosome
non-membranous organelle
cell wall: peptidoglycan
binary fission
bacteriasimple, dynamic, well adapted for survival and new environment
archaeapseudopeptidoglycan, extreme environment
eukaryotic
nucleus
multiple chromosomes
membranous and non-membranous organelle
no peptidoglycan
mitosis
algaephotosynthetic, pigment, cellulose
funginatural decomposer, chitin cell wall, absorbs organic material
protozoano rigid cell wall, free entities or parasites, ingests particles as food
non-living component: infectious agents
virusparticles with a protein coat (capsid) and genetic material
viroidRNA, no protein (infects plant only)
prionsprotein, no genetic material
2.Cell morphology: determine by gene and environment conditions
coccusspherical
diplococcitwo
streptococcichain
sarcinacuboidal
tetradfour
staphylococcigrape clustered
bacillusrod-like
coccobacillusoval
diplobacillitwo
streptobacillichain
palisadesladder
spirillumspiral < 20 turns
spirochetespiral > 20 turns
pleomorphicvariation in size and shape
3.Cell structure
appendages
fimbriaefacilitate attachment, few-thousands, adhesin, pilin proteins
pilifacilitate conjugation, 1-10
flagellawhip-like structures for motility
filament, hook, basal body (G+ one pair ring, G- two pair ring)
monotrichousone
peritrichousmultiple all-over
amphitrichousboth pole
lophotrichousmultiple on one pole
taxissensing and responding to stimuli
chemotaxischemical
phototaxislight
aerotaxisoxygen
magneto taxismagnetic field
endoflagellapresent in spirochetes
Treponema pallidum, Borrelia burgdorferi
rotation causes the axial filament to rotate around the bacterium
cork screw motion to drill into viscous tissues of host
cell envelope
glycocalyx is viscous, gelatinous material, mainly polysaccharide
synthesized inside cell and secreted outside onto cell surface
protection from phagocytosis
viscous gelatinous nature
slippery nature
mimic chemical composition of host cell
prevent lysosome infusion
protects cell from dehydration
critical role during initial attachment
can serves as a nutrient source
slime layerdisorganized and loosely attached
capsulewell structured and firmly attached to cell wall
cell wall
Gram positive
multi-layer peptidoglycan (negative charge)
rigidity and mechanical stability
backboneNAG, NAM disaccharide, O-glycosidic
tailtetrapeptide NAM L-aa, D-aa, L-aa, D-aa
bridgeindirect crosslink 3rd-aa to 4th-aa
PBPpenicillian binding protein
free passage of substances (sugar, ions, amino acids)
3rd-aa always L-lysine
wide variation in bridge amino acid sequence
teichoic acids polymer of sugar/glycerol phosphate with D-alanine
lipoteichoic acidspan the thick peptidoglycan layer
wall teichoic acidconfined to the peptidoglycan layer
regulates + charged ions movement into and out
attachment site for many bacteriophages
antigenic specificity that activities and alerts our immune system
Gram negative
outer membrane (negative charge)
lipopolysaccharides (outer) + phospholipid (inner)
polysaccharide portion, O-antigen
target for...
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