Exam II Flashcards
(138 cards)
What is the name of Complex I? What reactions happen there? What is the net equation?
Complex I is NADH-Q oxidoreductase/NADH dehydrogenase There are three reactions: Rx 1: oxidation NADH Rx 2. Reduction of coenzyme Q Rx 3: proton pumping
Net reaction:
NADH + Q + 5H+ (matrix)»_space; NAD+ + QH2 + 4H+ (cytosol)
What is the name of complex II? What is the net reaction?
Complex II is Succinate dehydrogenase or succinate-Q reductase complex
Net reaction:
succinate + Q»_space;> fumarate + QH2 (without proton pumping)
What is the name of Complex III? What are its prosthetic groups? What are its P site and N site?
Complex III is CoQ-cytochrome c oxidoreductase or cytochrome b-c1 reductase
Heme c1, bL, bH, Reiske Iron-sulfur center
Positive site is where electron goes to reduce cytochrome c. Negative site is where electron forms radical.
What is the net reaction of the Q cycle of Complex III?
QH2 + 2 Cyt (ox) + 2H+ (matrix)»_space; Q + 2 Cyt c (red) + 4H+ (cytosol) (four protons are pumped out)
What is the name of complex IV? what does it do
Complex IV is cytochrome c oxidase or cytochrome oxidase. It transfers electrons to oxygen molecule from cytochrome C, which carries only one electron.
What is the net reaction of complex IV? Per NADH?
Net reaction:
4 cyt c (reduced) + O2 + 8H+»_space; 4 cyt c (oxidized) + H2O + 4 H+ (cytosol)
per NADH, however, since cyt is a one electron carrier and we needed four, and each NADH only carries two electrons, we pump 2 H+ into cytosol.
Summary of ETC reaction for NADH
NADH + 11 H+ (m) + 1/2 O2»_space; NAD+ + H2O + 10H+ (c)
Summary of ETC reaction for FADH2
FADH2 + 6 H+(m) + 1/2 O2»_space; FAD + H2O + 6H+ (c)
What are inhibitors of Complex I (3)?
Amytal, barbiturate
Rotenone, insecticide, pesticide and piscicide
MPP+, neurotoxic drug metabolite from MPPP
(ARM)
What is an inhibitor of Complex II?
Malonate, a competitive inhibitor of Complex II, from alfalfa leaves (melon)
What is an inhibitor of Complex III?
Antimycin A, produced by strep bacteria, binds to N site of Complex III (ANT)
What are inhibitors of Complex IV? (3)
cyanide, azide, carbon monoxide (Coconut)
disease caused by mutation to complex I?
LHON (blindness), Leigh Syndrome (impaired motor skills), MELAS
disease caused by mutation to complex II?
Leigh Syndrome
disease caused by mutation to complex III?
LHON, Encephalomyopathy
disease caused by mutation to complex IV?
encephalomyopathy, myopathy (muscle dysfunction)
delta G of oxidation of NADH?
-52.6 kcal/mol
What is the relationship between Gibbs Free Energy Change and the proton motive force?
proton motive force (deltaP) = deltaG/nF
The more deltaG, the more deltaP
What are four inhibitors of ATP synthase? How do they work?
oligomycin - binds to Fo, blocking protons from coming in
Aurovertin B - binds to Beta subunit, inhibits conformational change
DCCD - modifies carboxyl groups in protein
IF-1 - (upon onset of myocardial ischemic process) (stroke), what happens is the proton gradient has been flipped, so ATPase will now want hydrolyze ATP. IF-1 binds to the alpha, beta and gamma proteins of F1, preventing their conformation change. This is all under low oxygen conditions.
What are the four carriers of inner membrane of mitochondria? What do they transport?
ATP-ADP translocase (ANT) - ADP into m, ATP into c
Dicarboxylate carrier - Phosphate/Malate
Tricarboxylate carrier - Malate/Citrate + H+
Phosphate carrier - Phosphate/ OH-
What blocks the ATP/ADP exchange, inhibiting ATP/ADP exchange?
atractyloside and bonkrekic acid
How many cytosolic ATPs are produced per oxidation of 1 matrix NADH?
~2.5 cytoplasmic ATPs
How many cytosolic ATPs are produced per oxidation of 1 matrix NADH?
~1.5 ATPs
How does NADH from cytosol get into mitochondrial matrix of heart and liver cells? How many ATPs does it yield?
malate-aspartate shuttle
P/O ratio is ~ 2.5 ATPs