oxidative phosphorylation

Question 1

where does oxidative phosphorylation occur what does it require, and major role?

Answer 1

-requires oxygen, final stage of aerobic respiration
-to make ATP by oxidative phosphorylation
-occurs on the cristae on the inner membrane

Question 2

what is embedded in the inner membrane?

Answer 2

-electron carrier proteins (cytochrome c)= oxido-reductase enzymes containing haem group with iron
-ATP synthase enzymes

Question 3

describe the process of oxidative phosphorylation

Answer 3

-reduced NAD carries hydrogen to the electron transport chain from krebs cycle
-hydrogen unbinds from NAD and dissociated into H+ and electrons = NAD is reoxidised
-electrons pass down the electron carriers in the electron transport chain and lose energy as they go
-energy lost by electrons is used to pump H+ into the intermembrane space from matrix where the concentration of H+ builds up (electrochemical gradient)
-at end of electron transport chain the electron binds with the e- acceptor, oxygen, and hydrogen forming H2O
-the H+ in the intermembrane space will move from the region of higher conc to lower conc in the matrix but the inner membrane is impermeable to H+
-so the H+ have to pass through ATP synthase which is embedded in the inner membrane
-the movement of the H+ (proton motive force) causes the ATP synthase to spin and energy released allows the phosphorylation of ADP to ATP

Question 4

What is chemiosmosis

Answer 4

when the hydrogen ions flow from the intermembrane space through ATP synthase enzymes into the matrix

Question 5

what are the products and overall yields of oxidative phosphorylation

Answer 5

-10 NAD
-2 FAD
Water

Question 6

why is oxygen important in the ETC

Answer 6

its the final electron acceptor-without it, ETC cannot continue as electrons are not removed from the end

Question 7

how many ATP does each molecule of NAD and FAD generate per molecule? and so what is the total ATP during electron transport chain

Answer 7

-NAD = 2.5 ATP
-FAD = 1.5 ATP

glycolysis= 2 NADH 0 FADH= 5 ATP
Link= 2 NADH 0 FADH = 5 ATP
Krebs= 6 NADH 2 FADH = 18 ATP
TOTAL ATP= 28 ATP

ATPs made during glycolysis, link, krebs =4

total overall ATP by aerobic respiration= 32 ATP

Question 8

Why is the actual yield less (closer to 30)

Answer 8

-some ATP is used to actively transport pyruvate into mitochondria
-some ATP is used to transport reduced NAD made during glycolysis into the mitochondria
-some protons may leak out through the outer mitochondrial membrane