functional morphology of prokaryotes Flashcards
2 major structural differences between prok and euk
- prok have no defined organelles.
2. prok are generally much smaller in size.
structure of prok
simpler than eul.
nucleoid, not bound. sometimes have plasmid, have cell wall.
structure of euk
sometimes have cell wall depending on euk.
have ER, golgi, mt and true nucleus
how S/V ratio affects prok growth
larger SA/V ratio = outside interacting with more of enviro, more nutrients + greater concentration gradient.
why do euk want to be bigger w smaller s/v ratio?
eat other smaller cells, more complex + specialized. sacrifice growth for increased complexity.
what constrains sie of prok?
ribosomes = can be as small as few proteins, cell membrane + at least 1 ribosome. but need these 3 to function + be called bacteria.
morphologies of prok cells
coccus, rod, spirillum, filamentous, stalk, hypha, spirochete
spirochetes : 2 ex organisms
treponema pallidum (syphilis) + borrelia burgdorferi (lyme disease) -> drill into muscle cells + cause disease
vibrio - bent rod. ex organism?
vibrio cholerae = diarrhea
cocci, cluster or pair or chain or tetrad
cluster = staphylo, pais = diplo. chain = strepto. tetrad = sarcina
appendaged/budding
growth stalk attaches to surface.. or bud - pillus cell buds off until settles somewhere else.
filamentous
chloroflexus: photosynthetic, ancient
define monomorphic
one shape, observed in pure cultures
define pleomorphic
multiple shapes.
-chage during growth. response to enviro cues: sporulation (nutrient limitation)
example of pleomorphic organism?
arthrobacter sp. morphogenesis from rod to coccus during growth3
macromolecules in prokaryotes
protein. nucleic acid (dna in nucleiod; rna in cytoplasm), polysacch: cell wall + storage. lipids = cytoplasmic membrane, cell wall, storage
permeability barrier
prevent leakage + transport of nutrients in + out
protein anchor in bacterial membrane
site of proteins involved in transport, bioenergetics + chemotaxis anchored to function externally
three functions of bacterial membrane
permeabiltiy barrier, protein anchor, energy conservation
energy conservation in bacterial membrane
generation + use of pmf
membrane chemistry = ester vs ether
ester = bacteria + eukarya.
ether : archaea = isoprene chain, more complex + stable
archaea - monolayer vs bilayer
bilayer = two shorter chains. hydrophobic inside, hydrophilic inside. monolayer = one long chain with 2 hydrophilic parts. must move in one piece = harder to move
function of hopanoids?
rigidity to otherwise flexible membrane due to planar configuration
euk: cholesterol (three 6-memer, 1 5-member)
bacteria: diploptene (four 6-member, 1 5-member)
rate of transport for water, uncharged non-polar, charged non-polar
excellent; uncharged: fair; charged = extremely poor.
transporters require energy = what is energy used?
proton motive force to generate ATP.
what is simple transport?
driven by energy in porton motive force
what is group translocation?
chemical modification of the transported substance driven by phosphoenolpyruvate.
The ABC system: periplasmic binding proteins are involved and energy comes from ATP
periplasmic binding proteins are involved and energy comes from ATP.
three mechanisms of simple transport driven by PMF
uniporter, antiporter, symporter
group translocation - ex: the phosphotransferase system
glucose interacts with E2c. signal to begin phosphorylation process. E2c change in conformaiton = change in e2b -> e2a. once e2a conformation change, interact with HPR = attracts enz 1. enz 1 hydrolyzes PEP -> pyruvate and carries Pi across back to E2c where Pi added to glucose + complex carried across membrane
ABC (ATP -binding cassette) transport.
- which bacteria? why?
only in g(-) bacteria.
occurs in periplasmic space. in g(-) because have larger ppspace. molecule binds to specific binding protein = complex; attaches to membrane-spanning transporter. ATP hydrolysis leads molecule to shift thru transporter
transport across the membrane = limited why?
carrier saturation. max growth rate, or all transporters full.
who made gram stain? what is procedure?
christian gram.
1. stain with violet-iodine. binds to membrane.
in g(+): goes thru pg layer = no leaking when washed.
cells decolorized with alcohol: g+ dehydrated - prevent escape of purple dye.
3. counter stain with safranin - pink = g(-)
important physiological differences btw g(+) and g(-) bacteria
- g(+) more susceptible to b-lactam.
+: in spore form more resistant to heat + mechanical stress.
+ require additional vitamins or AA for growth
g(-) more widespread.
how PG is made?
glycan = NAM + NAG disaccharides bonded by b(1,4) glycosidic bonds.
- > AA link to NAM. L - Alanine; D-glutamic acid; d-alanine, meso-diamino-pimelic acid (allows resistance to peptidase)
- significant that there’s D-aa. everywhere else there is :-aa.
PG in g+
-> connection?
l-ala; d-glut; l-lysine; d-ala.
peptide interbridge: 5 glycine. why? bc opposite handedness from L-lys to d- ala
pg in g(-)
l-ala; d-glutamic acid; meso-diaminomietic acid; d-ala
why strong structure in PG?
strong btw inter-linkage. also strong between sheets = bonds to strengthen.
2 main inhibitors in cell wall biosynthesis
lysozyme hydrolyzes b(1,4) glycosidic bond. growing + present bacteria
2. penicillin blocks transpeptidase that connects (DAP to D-ala) 2-glycan- linked peptide chains together. only hits growing bacteria
cell in lysozyme + sucrose solution ?
protoplast = bacteria without cell wall. cel wall digested
pseudoPG in some methanogenix archaea
b(1-3) linkage btw NAG and NAT prevent lysozyme attack.
not sensitive to lysozyme bc lysozyme hits b(1-4) resistant to penicillin = why? bc diff arrangement of aa in chain.
achaeal cell envelopes
without: cw, cm, cell plasma.
with: s-layer: bound by trans-membrane protein. proteinaceous on outside. space between s-layer and CM. similar stability + structure that CW and pseudo PG have.
g+ : what is teichoic acid?
component of Cw that gives flexibility. extends surface of cw , gives it negative charge.
lipoteichoic acis links cw + cm
g- cw: components?
cm - has TM protein in peiplasmic space.
PG - has lipoproteins that connect cw with outer membrane.
polysacchs on outer membrane interact with outside world. lipopolysacchs have lipid a core, core polysacch and o-polysachh. o-polysacch changes
lipopolysacchs of g- cw.
important
barrier agsint host defenses. lipid A = endotoxin to animals; reason for pathogenicity. o-specific polysacch varies.
order: lipid A (anchor to membrane) -> letodeoxyoctonate -> core -> o-specific (specific to particular chain)
what is a porin?
channel for entrance + exit of hydrophilic low molecular weight (<00daltons) substances (ie. water, ions) no proteins, large molecules
what’s in periplasmic space
enxymes that participate in nutrient acquisition + metabolism.
- small, essentially non-existent in g+. (bc cw bound to cm
chemolithotrophs - pp space
have extensive arras of e- transport proteins extending to outer membrane for uptake + metabolism of inorganic ions. oxidize toxic chemicals b enzymes in ppspace linked to outer membrane
g+ bacteria: exoenzymes?
secreted by cell to aid in transporting nutrients.
capsule + slime
produced by cell in organic rich enviro.
capsule/slime act as energy storage + protect against enviro, dehydration + organic material. = increase survival attachment + virulence.
one way to visualize capsule/slime
india ink - negative stain bc doesn’t penetrate capsule. everything but capule stained.
4 types of cellular inclusions
- carbon storage
- sulfur storage
- magnetosomes
- gas vesicles
function of carbon storage cell inclusion?
store carbon in different forms until needed.
bacteria + archaea
function of sulfur storage
sulfur granules stored for low sulfide consitions. some organisms use sulfide for ox-phos
function of magnetosomes
allow bacteria to orient + migrate along geomagnetic fields; usually associated with O2 concentrations.
function of gas vesicles
important for aquatic microorganisms. allows them to float in large colonies - buoyant.
float during day to get light, sink to bottom at night to feed
endospores - when do they occur? triggered when? g+ or -?
occurs as bacteria age due to nutrient deprivation. tigger is nutrient, not enviro stress.
all spore-forming are g+, but not all g+ are spore-formers.
endospore structure - 4 layers
spore coat; cortex; exosporium; core wall. = dehydrated, resistant to degradation
difference btw endospore + exospore
endo = formed inside cell. repackage DNA + pop out of vegetative cell exo = daughter cell is sport = ejected
what is dipicolinic acid?
READ IN TEXTBOOOK
aka DPA. - nitrogenous ring w carboxylic groups, charged.
unique to bacterial spores.
-> 10% dry weight of endospores.
-> high in calcium ion, crosslinks DPA
-> rigid structure. less availability for water - decreases damage to DNA + cell
shapes of endospores
central
subterminal
terminal bacillus: aerobic g+
terminal clostridium: anaerobic g+
ways in which endospores return to vegetative state
- heat endospore
- nutrient broth
- germination is rapid, synthesizes + breaks open spore coat.
pili - function?
form conjugation bridge between bacterial cells for transferring DNA and attach to host cells
-pillus formation depends on plasmid present.
types of flagella in bacteria
know this
- attached at one end.
- attached at both ends
- tuft at one end
- all around surface.
flagellum of g- bacteria - components
filament - flagellin.
hook - hook protein
basal body - 4 rings : L ring, P ring, MS ring, C ring.
motprotien around MS + C rings fli protein between MS and C rings
flagellum g-: function
pmf thru mot protein causes it to spin. interacts with Fli protein and causes it to spin in turn with MS ring.MS ring hold central column which turns too.p-ring allows column to go through. l-ring spans uter membrane. maintains structure + holds column in place.
hook area is where flagellin filament grows. proteins flow thru hollow column to end of hook
how pmf causes mot protein to move
ms and c-rings are charged. when H+ moves thru, electrostatic repulsion forces MOT protein to spin.
development of flagellum - g-
MS ring assembled in CM. ; P-ring forms in periplasm.; L-ring froms in LPS.; hook + cap (stops hook from forming, allows filament synthesis); flagellin thru hollow column to hook to form filament.
difference from g- to g+ flagellum.
no LPS, no outer mem.
only rights.
archaellum - contrast to flagellum
half the diameter; more by rotation. filament protein unrelated to bacterial. use ATP instead of pmf. FLAX protein hydrolyzes ATP causing spin of FLAX + FLAI structurally similar to Type 4 pilus.
what is type 4 pillus
pokes hole in CM and injects toxin, DNA etc.
diff mechanism than flagellum,, but similar function.
gliding motility - what organism?
flavobacterium johnsoniae.
-> driven by PMF.
protins in outer membrane move opposite to cell. outer mem attached to cm proteins, . again opposite motion. cm same direction as cell movement
axial filaments - where found?
endoflagella; found in spirochaetes. flagella is inside body, anchored at end of cell. drills + burrows into thiings by rotation of whole cell.
chemotaxis - what is it?
random cell movement in absence of attractant; attractant causes directed movement up-gradient.
by run-and-tumble method. flagella come together to push in one direction, disassemble, random motion to re-align. then run again.
petrichous movement- what is it?
read in textbook
all flagella rotate counterclockwise in a bundle.
when apart, reverse direction pulls apart - FLI protein changes direction
polar flagella - how do they work?
change direction by reversing rotation.
- polar reversible: ccw forward, cw backward.
- polar unidirectional: cw forward. stop, realign, cw forward
when u put capillary tube full of chemical in bacterial suspension - why is there saturation?
saturation of distance away bc only so far they can move toward or away from.
what is phototaxis
photosynthetic bacteria accumulate at wavelength where pigments abosrb.
one nutrient that’s limited + limiting?
Nitrogen.
Why is nitrogen limited?
bacteria can sequentially reduce nitrite into N-gas = lose nitrogen.
function of NO in organism?
toxic to other organisms.
potent greenhouse gas produced as result of denitrification?
N2O
discuss anaerobic respiration
dont use O2 as terminal e- acceptor.
because of this, less electropositive terminal acceptor is used, such as No3-. less energy is generated bc of a worse e- acceptor.
what organisms do anaerobic respiration?
prokaryotes
- > obligate anaerobes : cannot respire with O2
- > facultative aerobes: can respire with or without O2.
chemoorganotrophs + chemolithotrophs
how nitrate reduction is mediated through the cell
e- pass thru complex1 -> Fe-S -> Q -> cyt b (NOT C). fewer ATP produced at nitrate reductase
how denitrification is mediated through the cell
c1 -> Fe-S -> Q -> cyt b -> nitrate reductase (not cyt C), other cytochromes -> NO reductase.
*if continue to complete denitrificaiton = greater H+ graident + more ATP produced. costly on space in the membrane, and in genome. facultative usually stop of NO3 reductase. obligate anaerobes commit to whole denitrification process.
sulfate reduction
- > length?
- > what organisms use?
sulfate reducing ETC is short bc fewer ATP result from it.
-> sulfidogens + obligate anaerobes use
two major roles of TCA cycle
glucose respiration coupled to energy conservation + biosynthesis of key metabolites
define anapleurotic
used in both catabolism + anabolism
two problems with substrate-level phosphorylation
1 atp /2 gluose.
2 need to regenerate NAD+
phenol
disrupt h-bonding in protein. -> disinfect
alcohol
disrupt h-bond in protein and dissolve membrane lipids.
-> disinfect, antispetic
halogen
oxidize cell constituents. disinfect + antiseptic.
heavy metals
inactivate proteins - antiseptic
aldehyde + lactone
inactivate proteins.
sterilizing gases
bind to protein.
vapour-phase h2o2 + quaternary ammonium
disrupt biological membranes.
phenol
h-bond to denature protein - disinfect
alcohol
h-bond to denature protein + dissolve membrane -> anitseptic + disinfectant
halogen
oxidize ell constituent
