Microbiology ch4

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69 terms · Prokaryotes

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

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