Oxidative Phosphorylation Flashcards
What are the cofactors produced in the TCA cycle that are harvested for their high-energy electrons
NADH and FADH2
Which direction is the proton concentration gradient in the mitochondria
High in the intermembrane space and low in the matrix
Where does the energy come from which drives ATP synthase
Proton flow across the membrane
What is the benefit of having many steps in the electron transport chain
no large amounts of energy are produced at one time so no energy is wasted or lost
which direction in redox potential do electrons flow
from negative to more positive (thermodynamically favoured)
what are the benefits of the invaginations of the mitochondrial inner membrane
increase the surface area - more comlexes
allow the creation a proton imbalance
what are the two stages of oxidative phosphorylation
electron transport from NADH and FADH2 to O2 via the respiratory chain
ATP synthesis from the energy stored in the electrochemical gradient of protons
is ATP synthesis related to electron movement or proton movement
protons
when electrons flow along the respiratory chain what does this transfer of energy cause
conformational changes allowing the flow of protons across the membrane
what are the names of the four complexes of the respiratory chain
complex I - NADH-Q-reductase (Q = ubiquinone)
complex II - succinate dehydrogenase
complex III - cytochrome c reductase
complex IV - cytochrome c oxidase
what are the names of the two non-complex aspects of the respiratory chain
ubiquinone
cytochrome c
at which complexes do NADH and FADH2 enter the respiratory chain
NADH at complex I
FADH2 at complex II (because it has less energy)
which complex of the respiratory chain does not pump protons across the inner mitochondrial membrane
complex II (succinate dehydrogenase)
complex I and II both reduce what
ubiquinone
what does complex III reduce
cytochrome c
cytochrome c is oxidised by what
cytochrome c oxidase
which complex of the respiratory chain produces water by donating electrons to oxygen
cytochrome c oxidase (complex IV)
what is the only channel through which protons can move down they’re electrochemical gradient across the inner mitochondrial membrane
ATP synthase
which side of the inner mitochondrial membrane do protons ‘want’ to be on
matrix side
which is a stronger driving force for the flow of protons, charge or concentration (pH)
charge
where is each subunit of ATP synthase located
F1 - protruding into the mitochondrial matrix
F0 - in the inner mitochondrial membrane
what causes the F1 subunit of ATP synthase to rotate
the flow of protons through the F0 region proton channel
what does the rotation of the F1 subunit of ATP synthase cause
a conformational change and contraction which brings ADP and Pi close together producing ATP
what is the terminal electron acceptor in the respiratory chain
what does it produce
oxygen
water
what is the P/O ratio measurement of
the number of inorganic phosphates (P) incorporated into ATP per atom of oxygen (O) reduced
what is the P/O ratio if NADH is oxidised to NAD+
2.5
what is the P/O ratio if FADH2 is oxidised to FAD
1.5
What are the final yields of glycolysis and the TCA cycle (ATP, NADH + H+, FADH2)
Glycolysis: 2 ATP, 2 NADH + H+
Pyruvate dehydrogenase: 2 NADH + H+
TCA cycle: 6 NADH + H+, 2 FADH2, 2 ATP
Total: 4 ATP, 10 NADH + H+, 2 FADH2
What are the cofactors produced in the TCA cycle that are harvested for their high-energy electrons?
NADH and FADH2
