5.7.8 Oxidative Phosphorylation

Question 1

Where does oxidative phosphorylation take place?

Answer 1

In the inner mitochondrial membrane

Question 2

What does oxidative phosphorylation result in?

Answer 2

The production of many molecules of ATP and the production of water from oxygen

Question 3

What is the current model for oxidative phosphorylation

Answer 3

The chemiosmotic theory

Question 4

What is the chemiosmotic theory?

Answer 4

H atoms donated by reduced NAD and reduced FAD from Krebs cycle

Atoms split into ions and electrons

Energy from electrons (passed through the ETC)

This is used to pump protons (H) up conc gradient into intermembrane space

Hydrogens flow by facilitated diffusion through ATP synthase into matrix

Energy of hydrogens flowing down conc gradient is harnessed (like HEP) resulting in phosphorylation of ADP into ATP by ATP synthase

Oxygen = final electron acceptor. Combines with protons and electrons at end of ETC to form water

Question 5

What is the electron transport chain?

Answer 5

A series of membrane proteins that are positioned close together which allows the electrons to pass from carrier to carrier.
Inner membrane of mitochondira is impermeable to H ions so electron carriers are required to pump protons across the membrane to establish conc gradient.

Question 6

Why is oxygen important for aerobic respiration?

Answer 6

It acts as the final electron acceptor.
Without oxygen ETC cannot continue as electrons have nowhere to go.

Without O2 accepting electrons and protons NADH and FADH2 cannot be oxidised to regenerate NAD and FAD, so they cant be used in further oxygen transport