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69 terms

Microbiology ch4

Prokaryotes
STUDY
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histones
proteins that DNA wraps around in eukaryotes
all bacteria have
-cell membrane
-cytoplasm
-Ribosomes 70s
-at least one chromosome
structures found in most bacteria
-cell wall (all except one)
-surface coating or glycocalyx
structures found in some bacteria (vary)
-flagella
-pili
-fimbriae
-capsules
-slime layers
-inclusions
-actin cytoskeleton
-endospores
parts of flagella
-filament, hook (sheath), and basal body
filament
hair like extention made of protein on a flagella
monotrichous
single flagellum at one polar end of bacteria
lophotrichous
multiple branches or flagella at one end
peritrichous
multiple flagella all over cell
amphitrichous
multiple flagella at both polar ends
chemotaxis
-movement in response to a chemical stimulus
-positive or negative
phototaxis
-movement in response to a light stimulus (sunlight)
-positive of negative
axial filament
-chain of protein running from one side of the cell to another in the periplasmic space
-only found in spirochetes
pili
-made of the protein pilin and used in conjugation
conjugation
the direct transfer of DNA between two cells that are temporarily joined (donor and recipient must be complementary)
fimbriae
small bristle like fibers bacteria use to stick to each other and other surfaces (attachment)
glycocalyx
external coating of cell made of poylysaccharide units, protein, or both
slime layer
-a loose shield that protects some bacteria from loss of water and nutrients
-major fuctions is attachment
-secrete EPS (expopolysaccharide and become bioflim)
capsule
-thicker form of glycocalyx that is bound more tightly to the cell and is denser and thicker
-protect from phagocytes by hiding receptors
cell wall
-determine shape of bacteria
-provides strong structural support (pressure due to osmosis)
-rigid because of peptidoglyan
cross links
-in gram + only (gram - have direct peptide bond)
-made of tetrapeptide side chains liked together by andinterglycine bridge (TIT)
techoic acids
-charged acidic polysaccharide attached to the surface of the cell wall used to attract nutrients
- only found in gram +
lipoteichoic acid/ lipoproteins
anchor cell wall to cell membrane
Mycoplasmas
-lack cell walls
-free living
-can be grown in artificial media
-important medicals species = walking pneumonia
L-form
-when bacteria lose their cell wall
-naturally frome mutation or induced artificially by treatment
protoplast
gram positive in L-form
spheroplast
gram negative in L-form
outer membrane
-layer in gram negative that contains specialized polysaccharides and proteins that serve as a partial chemical sieve
-uppermost layer = LPS
(LPS: O-antigen~LipidA~fatty acid)
-innermost layer = phospholipid bilayer anchored by lipoproteins to the peptidoglycan layer with porins
LPS
lipopolysaccharides
cell membrane composition
phospholipid bilayer with carrier protiens embeded in it
cell membrane function
-site for energy reactiolns, nutrient proscessing, and synthesis
-regulate transport
-secretion
cell envelope can cause disease
ex: corynebacterium diphtheriae & streptococcus pygenes
cytoplasm
-gelatinous solution that provides cushion layer
-site of biochemical and sythetic activity in prokaryote
nucleoid
dense area of the cell where bacterial chromosome (single circular strand of DNA) is aggregated
plasmids
nonessentia,l circular, self-replicating strands of DNA that give the cell some type of advantage
two genus with "wax" layer. compostition?
-Mycobacterium and Nocardia
-lipid/wax layer of mycolic acid
type and function of bacteria
-70s (50s & 30s)
-protein synthesis
inclusion bodies
-storehaouse of organic nutrient compounds (or gas) during periods of abundance
granules
-type of inclusion body that packe inorganic compounds
metachromatic granuesl
-granules of Corynebacterium and Mycobacterium that stain a contrasting color in methylene blue
bacterial cytoskeleton
-actin cytoskeleton: long polymers of actin arranged inhelical ribbons around the cell that contribute to cell shape
three genus that release spores
-Bacillus, Clostridium
-Sporosarcina
endospore
-dormant stage of bacteria
sporulation
-process of spore formation
sporangium
-transition stage of sporulation where cortex of petidoglycan surrounds what will become the spore (protoplast)
germination
-the process of returing from the endospore stage back to a vegetative cell (requires germination agent and water)
coccus
roughly spherical
bacillus
rod shaped
coccobacillus
short and plump rods
vibrio
gently curved rod
spirillum
curviform or spiral shaped
pleomorphism
cells of a single species that can change shape
Bergey's Manual
-definitive published source for bacterial classification
tetrads
cluster of four cocci
sarcina
cubical packet of cocci
palisades
bacilli attached at sides
gracilicutes
gram negative
firmicute
gram positive
tenericutes
lack cell wall
menodicutes
the archae
4 divisions of prokaryotes
-gracilicute,firmicutes,tenericutes,mendocicutes
-based on nature of cell wall
species
-two like animals mate and produce a viable offspring
-for bacteria: a group of organisms that share similar growth characteristics
subspecies
-strain or type of bacteria or the same species that have a slight difference in growth characteristics
serotype
-representatives of a species that stimulate a distinct patter of antibody responses in their host (interaction between antigen and antibody)
rickettsias
-very tiny, gram negative, obligate parasites
-rocky mountain spotted fever -> Rickettsia reckettsii
-Endemic typhus ->Rickettsia typhi
chlamydias
-obligate parasites
-Chlamydia trachomatis -> severe eye infection and STD
-Chlamydophila pneumonia -> lung infection
thylakoids
disk-shaped structures that contain photosynthetic pigments
cyanobacteria
-blue-green photosynthetic bacteria that contains thylakoids with chorophyll a and have gas inclusions
-oxygenic
green and purple sulfur bacteria
-photosynthetic bacteria that contain the pigment bacteriochlorophyll
-anoxygenic