11.4-11.5: Regulation of Oxidative Phosphorylation Flashcards
how many trips through the electron transport chain are needed for completion?
2
what is ATP/ADP translocase? how does it work? (3)
- a dimeric antiporter
- works via the rocking bananas mechanism
- trades 1 ATP for 1 ADP to maintain a -1 charge differential on the cytosolic side of the membrane
list and describe the 2 states of ATP/ADP translocase
C state: imports 1 ADP to mitochondrial matrix from the intermembrane space; inhibited by atractyloside
M state: exports 1 ATP to intermembrane space from matrix; inhibited by bongkrekic acid
why is the ATP/ADP translocase anitporter mechanism favorable?
ATP is more negative than ADP and the cell wants to put more negative ATP on the p side to neutralize the positive charge there
what is phosphate translocase?
a channel protein that doubles as a symporter/antiporter
what type of active transporter is phosphate translocase?
a secondary active symporter that takes advantage of the proton gradient
when acting as a symporter, what does phosphate translocase transport?
Pi and H+
when acting as an antiporter, what does phosphate translocase transport?
Pi and OH-
explain why it takes 4H+ to yield 1 ATP in 3 points
- 1 H+ goes through a phosphate translocase to provide Pi for ATP synthesis (makes ATP)
- 3 H+ go through ATP synthase to catalyze the reaction (turn the rotor)
- so it takes 4 H+ dlowing from P side back to N side to produce 1 ATP
list the types and amounts of important molecules that glycolysis produces (3)
- 2 pyruvate
- 2 ATP
- 2 NADH
list the types and amounts of important molecules that 1 pyruvate can yield in conversion to acetyl-coA (that’s a hint) (2)
- 1 acetyl-CoA
- 1 NADH
list the types and amounts of important molecules that 1 Acetyl- CoA can yield through the citric acid cycle
- 3 NADH
- 1 FADH2
- 1 GTP
how many protons does one NADH yield through the electron transport chain?
10
how many protons does on FADH2 yield through the electron transport chain?
6
hwo many molecules of ATP does one NADH yield?
2.5
how many molecules of ATP does one FADH2 yield?
1.5
what is the net reaction for oxidative phosphorylation with NADH?
2 NADH + 2H+ + 5ADP + 5Pi + O2 –> 2 NAD+ + 5 ATP + 2H2O
what is the net reaction for oxidative phosphorylation with FADH2?
2 FADH2 + 3 ADP + 3 Pi + O2 –> 2 FAD + 3 ATP + 2 H2O
how does aerobic respiration generate ATP?
through electron carriers
can NADH from glycolysis cross the mitochondrial membrane to enter the electron transport chain alone? what does it do instead?
no; NADH from glycolysis must use shuttle systems to get its electrons across the mitochondrial membrane
what are the 2 shuttles that get the electrons from cytosolic NADH across the mitochondrial membrane to enter the electron transport chain?
- malate-aspartate shuttle
- glycerol-3-phosphate shuttle
where is the malate-aspartate shuttle used? (3)
liver, heart, kidney
how many H+ does the malate aspartate shuttle produce? how much ATP does this yield?
produces 10 H+; yields 2.5 ATP
where is the glycerol-3-phosphate shuttle used? (2)
muscles, skeletal tissue
compare the glycerol-3-phosphate shuttle to the malate-aspartate shuttle (2)
- NADH reduces FAD
- faster and less complex than malate-aspartate shuttle
how many H+ does the glycerol-3-phosphate shuttle produce? how many ATP does this yield?
produces 6 H+; yields 1.5 ATP
what is the net difference in ATP yield between ATP production in liver versus muscle? why?
ATP production in the liver yields 2 more ATP than ATP production in the muscle since the lvier uses the malate-aspartate shuttle to yield 2 more net ATP than the glycerol-3 phosphate shuttle used in muscle cells
what 2 compounds are needed in order for O2 consumption and subsequent ATP production? why?
both ADP + Pi AND succinate; need both the substrates and the entry into the electron transport chain
what does 2,4-dinitrophenol do? what is the result? (2)
uncouples oxidative phosphorylation;
1. H+ not transported
2. ATP not synthesized
what does cyanide do?
blocks complex IV and shuts down the electron transport chain
what does oligomycin do?
blocks ATP synthase
what is the result of addition of cyanide on O2 consumption and ATP synthesis?
O2 consumption: stops
ATP synthesis: stops
what is the result of addition of 2,4-dinitrophenol on O2 consumption and ATP synthesis?
O2 consumption: no effect (H+ just go somewhere else so)
ATP synthesis: stops
what is the result of addition of oligomycin on O2 consumption and ATP synthesis?
O2 consumption: stops
ATP synthesis: stops
