Escherichia coli Flashcards
shape and gram
rod, -ive
catalase and oxidase test
catalase +ive, oxidase -ive
3 other facts of E. coli
mesophile, facultative anaerobe, no growth factors needed
catabolism of sugars, what it can catabolized
can catabolized glucose using glycolysis and PPP, can synthesize LacZ so can catabolize lactose. if no sugars available, can catabolized gluconate using ED pathway
Facts of ETC, what it can synthesized (4)
branched ETC, synthesize dehydrogenase complexes eg NADH dehydrogenase, synthesize oxidase complexes, synthesize reductase complexes
aerobic respiration of E. coli
ETC branches to 2 diff oxidase complexes, Cytbo comlex is coupled to proton translocation (preferred), Cytbd complex is not coupled to proton translocation but has a higher affinity for O2 and is used when O2 [low]
anaerobic respiration of E. coli
E. coli can synthesize several diff reductase complexes depending on the TEA present
give two eg of anerobic respirate TEA
nitrate reductase uses nitrate (NO3-) as TEA. product nitrite. (NO2-) +ive nitrate reduction test. fumerate reductase uses fumerate as TEA. product is succinate
why doesO2 regulate the expression of terminal complexes
O2 inhibits the expression of any reductase. has the most +ive reduction potential
when is nitrate reductase synthesized but other reductases won’t?
without 02 and if nitrate is present
what can be used to donate e- to nitrate reductase. why
UQ or MQ, further down the tower, more +ive reduction potential
MQ must be used to donate e- to fumerate reductase why
if e- donor is NADH and fumerate is TEA then UQ is to +ive reduction potential, not -ive enough for -delta G. delta g btwen fumerate and UQ is +ive cannot be spontaneous requires nrg
what kind of fermentation?
mixed acid fermentation produces acid + gas
in a glucose phenol red broth what would you expect
yellow + gas. glucose fermentation
in a lactose phenol red broth what would you expect
yellow + gas, fermentation of lactose
