Biochemistry: Oxidative Phosphorylation Flashcards
how many electrons (NADH and FADH2) are produced from glycolysis and the TCA cycle
10 NADH+ and 2FADH2
each NADH+/FADH2 molecules carries two what
high energy bonds
how do NADH electrons from glycolysis cross into the inner mitochondrial membrane
- glycerol-3-phosphate shuttle
- malate-aspartate shuttle
describe the malate-aspartate shuttle
aspartate-> oxaloacetate -> malate (reduced by NADH+)
*crosses membrane
malate (oxidised by NAD+) -> oxaloacetate -> aspartate *crosses membrane
what is the electron transfer potential of NADH+ and FADH2 converted into
the phosphoryl transfer potential of ATP
how is the phosphoryl transfer potential of ATP measured
by measuring the free energy change of ATP hydrolysis
how is the electron transfer potential of a compound measured
by the redox potential
what is a redox potential
how readily a compound gives up an electron
describe the redox potentials of
- NADH+ + H+ and FADH2
- O2 and H2O
- negative - readily donates, strong reducer
- positive - strong oxidiser
describe the ETC
- NADH+ enters into the inner membrane at complex I, FADH2 at complex II
- these are proton pumps
- they then flow back through ATP synthase via the electrochemical gradient causing the rotor subunits to turn and generate ATP
- the H+, now back in the matrix, reduce O2 to H2O and energy is released
how do the proton pumps of the ETC get their energy
from the reduction of O2 by H+
what are cytochromes
enzymes containing haem as a cofactor
what does haem allow a substance to do as a cofactor and why
- allows it to take up and release electrons
- contain and Fe II ion
what are the two subunits of ATP synthase and where are they in the membrane
- F0 in the matrix
- F1 in the inner membrane (hydrophobic)
what inhibits oxidative posphorylation and how
- cyanide, CO and azide
- inhibits transfer of electrons to O2 and there for no ATP synthesis
- can inhibit different stages
