Studied by 5 peopleWhat is the proton motive force?
A combination of [H+] concentration gradient and electrical potential difference across IMS and Matrix
What does the F0 stalk of ATP Synthase do?
Acts as the motor by taking H+ via a subunit and sending it through the c ring
What AA exists on the C-ring that attaches protons to it?
Asp59
How many c subunits are in the c ring?
10
What are the subunits of the F1 portion of ATP synthase?
hexamer of α and β subunits, with γ subunit in the middle
What are the possible confirmations of the α and β subunits? Which way is the γ subunit turning in normal ATP synthesis?
Clockwise movement (O→L→T)
O: ADP + Pi bond (ATP released)
L: ADP + Pi locked
T: ATP formed
How much ATP does one full turn of ATP synthase form?
3 ATP
Which UCLA professor found the rotational ATP synthase model?
Paul Boyer
Do you know what the reaction coordinate diagram of ATP Synthase looks like?
This
How does ADP get to the mitrochondrial matrix?
Adenine Nucleotide Translocase transport 1 ATP into IMS and 1 ADP into matrix at the same time
How does inorganic Phosphate (Pi) transported into the matrix?
Phosphate Translocase Symporter transports 1 Pi in and 1 H+ out. It can also symport 3H+ for 1 ADP.
What 3 compounds form the ATP-synthasome complex?
ATP synthase, Adenine nucleotide translocase, and phosphate translocase
The ETC and TCA are said to be _____ coupled
Obligately
What does adding ADP + Pi do to ATP synthesis
Nothing
What does adding Succinate do to ATP synthesis?
ETC activate, increasing ATP synthesis
What does adding CN- do to ATP Synthesis?
ETC blocked, ATP synthe halts
What uncouplers can uncouple ETC from ATP Synthesis?
2,4 DNP and FCCP
What do uncouplers do?
Move H+ without the need for e-’s; destroys proton gradient
What do malate and aspartate do in the malate aspartate shuttle?
Transfer e-’s
How does NADH get into the mitochondrial matrix from the IMS?
The Malate-Aspartate shuttle and the G3P Shuttle
What does glutarate and a-ketoglutarate do in the malate-aspartate shuttle?
Amino group donors/acceptors
How much ATP does the Malate-Aspartate shuttle yield compared to the G3P Shuttle?
2.5 ATP compared to 1.5 ATP
Does the G3P shuttle need transporters?
No
Why does the G3P Shuttle produce less ATP than the Malate-Aspartate Shuttle?
It bypasses Complex I (misses out on proton pumping here)
What happens if no O2 is present?
Proton motive force collapses, stopping or reversing ATP synthase
If ATP Synthased is reversed (clockwise), what happens to ATP?
It is depleted by ATP Synthase
What genes are activated in hypoxic conditions that help with hypoxia? What do they do?
IF1 → binds ATP synthase dimers and stops reversal
HIF1 → Removes reactive Oxygen species by stopping PDH and replaced Subunit IV’s COX4-1 with COX4-2, which is better suited for low O2 concentrations
What is the total ATP yield?
30-32 ATP depending on which shuttle is used to bring NADH to ETC
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