18.4 Oxidative Phosphoylation

Question 1

What is oxidative phosphorylation

Answer 1

phosphorylation of ADP

for which energy is supplied

by electron transport chain

Question 2

Where does oxidative phosphorylation occur

Answer 2

In the cristae of mitochondria

Question 3

Outline the processes which occur during Oxidative Phosphorylation

Answer 3

NADH & FADH2 supply H atoms to cristae of mitochondria

H atoms dissociate ⟶ H+ + e-

These high-energy electrons take part in electron transport chain, releasing energy for active transport of H+ across mitochondrial membrane.

H+ diffuse through ATP synthase protein, driving the phosphorylation of ADP ⟶ ATP by chemiosmosis.

At end of electron transport chain, electrons combine with H atoms (delivered from coenzymes) + O2 ⟶ H2O
O2 is final electron acceptor, without it the electron transport chain cannot occur.

Question 4

What’s the final electron acceptor in the electron transport chain

Answer 4

Oxygen

Question 5

What supplies the H+ + e- to the electron transport chain in the mitochondria?

Answer 5

Coenzymes reduced NAD & reduced FAD

(NADH + FADH2 release hydrogen atom(s), which dissociate into H+ for the proton gradient and e- for the electron transport chain)

Question 6

What’s substrate level phosphorylation

Answer 6

Phosphorylation of ADP to ATP
Using a phosphate from a short lived highly reactive intermediate

Question 7

Why does FADH2 not synthesis as many ATP molecules as NADH

Answer 7

FADH2 supplies electrons to the electron transport chain further on than NADH

electrons from FADH2 release less energy

less H+ are actively transported across thylakoid membrane to create proton gradient

less H+ diffuse by facilitated diffusion through ATP synthase protein

less ATP molecules produced