5.2.6

Oxidative Phosphorylation

Test yourself on Oxidative Phosphorylation

Test your knowledge with free interactive questions on Seneca — used by over 10 million students.

Oxidative Phosphorylation

Oxidative phosphorylation is the final stage in aerobic respiration.

Inner mitochondrial membrane

Inner mitochondrial membrane

  • Oxidative phosphorylation takes place at the inner mitochondrial membrane.
  • There are several features of the membrane that allows production of ATP on a large scale:
    • Three electron carrier proteins (electron transport chain, ETC).
    • ATP synthase enzyme.
  • The space between the inner and outer mitochondrial membranes is called the intermembrane space.
Electron transport chain

Electron transport chain

  • NADH and FADH2 (from the Krebs cycle) are oxidised by the first electron carrier protein in the inner mitochondrial membrane.
  • This initiates oxidative phosphorylation because NADH and FADH2 release two protons and two electrons each.
  • The electrons are then transferred along the ETC.
Proton gradient

Proton gradient

  • As the electrons move down the ETC, they lose energy.
  • This energy pumps the protons from NADH and FADH2 into the intermembrane space.
  • This creates a proton gradient (also known as an electrochemical gradient).
Chemiosmosis

Chemiosmosis

  • The protons diffuse down the concentration gradient through the ATP synthase enzyme.
  • As protons flow through the ATP synthase, energy is released.
  • This energy converts ADP and inorganic phosphate to ATP.
  • This process is called chemiosmosis.
The final electron acceptor

The final electron acceptor

  • After the electrons have reached the end of the ETC and protons have flowed through the ATP synthase enzyme, they combine with O2 to form water (H2O).
    • Oxygen is called the final electron acceptor for this reason.
Jump to other topics
1

Biological Molecules

2

Cells

3

Substance Exchange

4

Genetic Information & Variation

5

Energy Transfers (A2 only)

6

Responding to Change (A2 only)

7

Genetics & Ecosystems (A2 only)

8

The Control of Gene Expression (A2 only)

9

Mathematical Skills

Practice questions on Oxidative Phosphorylation

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
  2. 2
  3. 3
Answer all questions on Oxidative Phosphorylation

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium