Practical 2 Flashcards
Complex 1
NADH dehydrogenase P:O= 2.5 RCR= 5-8 substrate :NADH/ glutamate/ malate electron carrier: FMN,FeS H+ movement: 4
Complex 2
Succinate dehydrogenase P:O= 1.5 RCR= 3-5 substrate :succinate to fumarate electron carrier: FADH,FeS H+ movement: none
complex 3
Q oxidoreductase P:O= NA RCR= NA substrate :QH2 electron carrier: cyt b, FeS, cyt C1 H+ movement: 4 (from 2x QH2)
Complex 4
cytochrome oxidase P:O= 0.5 RCR= 1-2 substrate :ascorbate, TMPD reduce cyt c electron carrier: Cu, cyt a, cyt a3 H+ movement: 2
Complex 1 product
QH2 for complex 3
complex 2 product
QH2 for complex 3
Complex 3 product
2e for cyt c, 2 e stays behind in complex 3
complex 4 product
water
complex 1 inhibitor
rotenone, irreversibly blocks 2e from FMN to FeS
complex 2 inhibitor
malonate
complex 3 inhibitor
antimycin, blocks 2e moving from cyt b1 to cyt bh
complex 4 inhibitors
cyanide
uncouplers
2,3 DNP
Oligomycin
P:O ratio
moles of ADP added/ moles of oxygen consumed in state 3
theoretical P:O calculation
number of H+ ejected during ETC/ number of H+ used to synthesise each ATP
Can use alternative calculation as assumed that all ADP added is converted to ATP when electron donor substrate is oxidised, and hydrolysis back to ADP is at negligible rate
respiratory control ratio
state 3 resp rate/ state 4 resp rate
why is calcium taken up by mitochondria?
causes stimulation in oxygen consumption
important to remove excess superoxide from mitochondria using enzyme
excess calcium uptake causes
opening of MOMP= mitochondria swells and uncouples, increasing in volume. Adenine nucleotide translocator (which exports ATP from mitochondria in exchange for ATP entry)
loss of cytochrome c= inhibits respiration and can induce apoptosis
effect of oligomycin
inhibits proton transport through Fo transmembrane complex of FoF1 ATPase
how do uncouplers work
lead to consumption of O2 as H+ can leak through membrane by binding to DNP (which is lipophilic)
H+ has higher affinity for DNP than F0F1
