SECTION 10 Flashcards
spherical bacteria
coccus or cocci
rod shaped bacteria
bacillus or bacilli
spiral
spirochete or spirochetes
function of the cell wall in bacteria
shape maintenance and protections from trauma and prevents swelling and bursting in hypotonic enviroments
what does the cell wall not do in bacteria
it cant prevent shrinking in hypertonic enviroments
what are the imporatnt compontents of bacteial cell walls
peptide glycan
what is peptide glycan
framework of modified sugar polymers linked by short polyppetides . tough, provides protection and anchorage for other molecules
what do archaea cell walls have
made of polysaccharides and proteins byt not peptidoglycan
gram positive
bacteria with thick cell walls
gram negative
bacteria with much less peptidoglycan
what stains are used in gram tests
crystal violet and iodine
steps of gram tests
add stains and wash with alchohol. if it stays purple that means its gram positive bc the stain is trapped nad if it is not purple that means the dye washed out and the cells are exposed to a safranin dye to be stained pink
what does penicillin work on
gram positive bacteria
what are the chemical implications of gram negative bacteria
the liposaccharides in the outer membrane of the cell wall can be toxic (endotoxins) and produce inflammatory response
what is the sticky outer layer secreted outside the cell wall of bacteria
polysaccharide or protein
capsule
if outer layer is dense and well defined
slime layer
if gooey and less structural and can be washed off
what are the two types of glycocalyx
capsule and slime layer
what is the fnction of a glycocalyx
protection : against dehydration agaiansts hosts immune system (cloak) virulence factor
attatchemnt: helps bacterium stick to substrate or other bacteria to form a colony
what are the hair like extensions on bacteria called
fimbriae and pili
what is the function of fimbriae
attatchment either onto other bactetria (to form a colony) or on specific host cell surface structures
adhesins
the attatchement molecules at the end of fimbriae. they act as virulence factors- without them many harmful bacteria lose their disease causing ability
pili
longer than fimbriae
what is the function of pili
form a mating bridge and function to pass genetic material between bactieral partners
where are fimbriae and pili formed
they are protein extensions formed outside the bacterium
endospore
form inside bacterial cells. cell copies its DNA and packages it into a tough cell wall and removes water to inhibit metabolism. The cell then dies and endospore is released. once environmental conditions improve, the cues to prompt rehydration and started and the cell resumes existence
what is taxis
directional movement
what are the ways that bacteira move
by gliding over the substrate, twitching, and swimming
how to bacteria swim
using flagella
what is a trait of prokaryotic flagella
they can rotate 360 degrees
what are prokaryotic flagella made of
- fillament: made of the protein flagellin
- hook: links filament to motor
3motor: set of protein rings at the surface of the bacterium
how do prokaryotes have internal organization
they have specialized infoldings of the plasma membrane carrying enzymes dedicated to performing specific functions
examples of infoldings in prokaryotes
infoldings that functin in cellular respiration (aerobic prokaryotes) like mitochondria and
infoldings called thylakoid membranes found in photosynthetic cyanobacteria. similar to chloroplasts
plasmids
additional little rings of DNA in the cytoplasm that contain contingency genes
what are contingency genes
genes not involved in the day to day running of the cell. they are involved in developing antibiotic resistance, becoming virulent, breaking down unusla substances
3 other ways that bactiera increase their diversity
- transformation
- trandsduction
- conjugation
all three involve horizontal gene transfer and genetic recombination
energy sources
chemical compounts (food- organic or inorganic chemical compounds) sunshine
carbon sources
food (preformed organic molecules)
inorganic carbon based molecules (co2)
three parts of a name of nutritional modes of living organisms
- energy source
- carbon source
- troph (nutrition)
sunlight energy source
photo
chemical compound energy source (organic or inorganic)
chemo
carbon dioxide carbon source
auto
organic sources (food) of carbon
hetero
what types of organisms are photoautotrophs
cyanobacteria, plants, some protists
what types of organisms are photoheterotrophs
only prokaryotes
what types of organisms are chemoautotrophs
only prokaryotes
what types of organisms are chemoheterotrophs
animals, some plants, some protists and E.coli
what bacteria can fix nitrogen
anabaena
what genes do anabaena have
gens for photosynthesis and genes for nitrogen fixation
what do anabaena convert into NH3
N2
what is nitrogen called
a limiting element
what is a vital ecological role of bacteria
nitrogen fixation
what are heeterocysts
the anabaena that carry out nitrogen fixation. they have thick cell walls
why do heterocysts have thick cell walls
to protect them from toxic O2 produced during photosynthesis of neighbouring cells which would irreversibly bind to the nitrogenase enzymes involved in nitrogen fixation
anaerobes
prokaryotes that are poisoned by oxygen. they use fermentation to make their ATP
what are facaultative anaerobes
bacteria that can make ATP with or without oxygen
what types of trophs are decomposers
chemoheterotrophs
what to decomposers do
secrete enzymes to break down the organic molecules in dead organisms and absorb what they need and release inorganic molecules back into the environment
what do producers do
convert inorganic molecules into forms that can be take up and used by other organisms. example is cyanobacteria
what is known as primary production
photosyntheis
what is the original source of atmospheric oxygen
cyanobacteira
symbiosis
ecological releationship in which organisms of two different species live together in intimate physical contact
bacteroids thetaoitamicron
bacteria that synthesize carbs, vitamins and other nutrients which we use. they produce signal molecules that stimulate our intestine ot produce blood vessels which help increase absorption of nutrients. stimulate us to produce antimicrobial to kill their competition
what domain are pathogenic prokaryotes in
all bacteria none arhcaea
what are the disease causing toxins produced by bacteria
exo and endotoxins
what are exotoxins and what do they do
exotoxins are toxic proteins escreted direcctly into the host by live bacteria. these disrupt essential processes sometimes fatally
what are exotoxins and enodtoxins
disease causing poisons
what happens when gram negative bacteria die
they break down and release endotoxins- the outer lipopolysaccharide membrane which enters the blood stream and can cause severe inflammatory responses
