Oxidative Phosphorylation

Question 1

Where does it occur?

Answer 1

Inner Mitochondrial Membrane

Question 2

What happens in Oxidative Phosphorylation?

Answer 2

• Hydrogen atoms from NADH and FADH2 released
• H atoms split to H+ ions and electrons
• Electrons enter electron transport chain
• Energy released used to transport H+ ions across inner mitochondrial membrane from matrix to intermembrane space
• Concentration of protons between these 2 cause protons to diffuse by facilitated diffusion through channel protein ATP Synthase
• As H+ diffuses through ATP Synthase, conformational change in its shape occurs allowing ADP and Pi to combine forming ATP
• Movement of protons down concentration gradient provides energy for ATP synthesis
• Oxygen is the final electron acceptor and combines with protons and electrons at the end of the electron transport chain to form water.

Question 3

What is the chemiosmotic theory? (short)

Answer 3

• Energy from electrons passed through electron transport chain is used to pump H+ ions against concentration gradient from mitochondrial matrix to intermembrane space
• H+ ions then diffuse via facilitated diffusion through ATP Synthase transport proteins back into the matrix
• Energy of H+ ions flowing down concentration gradient results in phosphorylation of ADP into ATP by ATP Synthase