11.4-11.5: Regulation of Oxidative Phosphorylation

Question 1

how many trips through the electron transport chain are needed for completion?

Answer 1

2

Question 2

what is ATP/ADP translocase? how does it work? (3)

Answer 2

1. a dimeric antiporter
2. works via the rocking bananas mechanism
3. trades 1 ATP for 1 ADP to maintain a -1 charge differential on the cytosolic side of the membrane

Question 3

list and describe the 2 states of ATP/ADP translocase

Answer 3

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

Question 4

why is the ATP/ADP translocase anitporter mechanism favorable?

Answer 4

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

Question 5

what is phosphate translocase?

Answer 5

a channel protein that doubles as a symporter/antiporter

Question 6

what type of active transporter is phosphate translocase?

Answer 6

a secondary active symporter that takes advantage of the proton gradient

Question 7

when acting as a symporter, what does phosphate translocase transport?

Answer 7

Pi and H+

Question 8

when acting as an antiporter, what does phosphate translocase transport?

Answer 8

Pi and OH-

Question 9

explain why it takes 4H+ to yield 1 ATP in 3 points

Answer 9

1. 1 H+ goes through a phosphate translocase to provide Pi for ATP synthesis (makes ATP)
2. 3 H+ go through ATP synthase to catalyze the reaction (turn the rotor)
3. so it takes 4 H+ dlowing from P side back to N side to produce 1 ATP

Question 10

list the types and amounts of important molecules that glycolysis produces (3)

Answer 10

1. 2 pyruvate
2. 2 ATP
3. 2 NADH

Question 11

list the types and amounts of important molecules that 1 pyruvate can yield in conversion to acetyl-coA (that’s a hint) (2)

Answer 11

1. 1 acetyl-CoA
2. 1 NADH

Question 12

list the types and amounts of important molecules that 1 Acetyl- CoA can yield through the citric acid cycle

Answer 12

1. 3 NADH
2. 1 FADH2
3. 1 GTP

Question 13

how many protons does one NADH yield through the electron transport chain?

Answer 13

10

Question 14

how many protons does on FADH2 yield through the electron transport chain?

Answer 14

6

Question 15

hwo many molecules of ATP does one NADH yield?

Answer 15

2.5

Question 16

how many molecules of ATP does one FADH2 yield?

Answer 16

1.5

Question 17

what is the net reaction for oxidative phosphorylation with NADH?

Answer 17

2 NADH + 2H+ + 5ADP + 5Pi + O2 –> 2 NAD+ + 5 ATP + 2H2O

Question 18

what is the net reaction for oxidative phosphorylation with FADH2?

Answer 18

2 FADH2 + 3 ADP + 3 Pi + O2 –> 2 FAD + 3 ATP + 2 H2O

Question 19

how does aerobic respiration generate ATP?

Answer 19

through electron carriers

Question 20

can NADH from glycolysis cross the mitochondrial membrane to enter the electron transport chain alone? what does it do instead?

Answer 20

no; NADH from glycolysis must use shuttle systems to get its electrons across the mitochondrial membrane

Question 21

what are the 2 shuttles that get the electrons from cytosolic NADH across the mitochondrial membrane to enter the electron transport chain?

Answer 21

1. malate-aspartate shuttle
2. glycerol-3-phosphate shuttle

Question 22

where is the malate-aspartate shuttle used? (3)

Answer 22

liver, heart, kidney

Question 23

how many H+ does the malate aspartate shuttle produce? how much ATP does this yield?

Answer 23

produces 10 H+; yields 2.5 ATP

Question 24

where is the glycerol-3-phosphate shuttle used? (2)

Answer 24

muscles, skeletal tissue

Question 25

compare the glycerol-3-phosphate shuttle to the malate-aspartate shuttle (2)

Answer 25

1. NADH reduces FAD
2. faster and less complex than malate-aspartate shuttle

Question 26

how many H+ does the glycerol-3-phosphate shuttle produce? how many ATP does this yield?

Answer 26

produces 6 H+; yields 1.5 ATP

Question 27

what is the net difference in ATP yield between ATP production in liver versus muscle? why?

Answer 27

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

Question 28

what 2 compounds are needed in order for O2 consumption and subsequent ATP production? why?

Answer 28

both ADP + Pi AND succinate; need both the substrates and the entry into the electron transport chain

Question 29

what does 2,4-dinitrophenol do? what is the result? (2)

Answer 29

uncouples oxidative phosphorylation;
1. H+ not transported
2. ATP not synthesized

Question 30

what does cyanide do?

Answer 30

blocks complex IV and shuts down the electron transport chain

Question 31

what does oligomycin do?

Answer 31

blocks ATP synthase

Question 32

what is the result of addition of cyanide on O2 consumption and ATP synthesis?

Answer 32

O2 consumption: stops
ATP synthesis: stops

Question 33

what is the result of addition of 2,4-dinitrophenol on O2 consumption and ATP synthesis?

Answer 33

O2 consumption: no effect (H+ just go somewhere else so)
ATP synthesis: stops

Question 34

what is the result of addition of oligomycin on O2 consumption and ATP synthesis?

Answer 34

O2 consumption: stops
ATP synthesis: stops