Question

What is the difference between photophosphorylation and oxidative phosphorylation?

Answer 1

Photophosphorylation occurs during photosynthesis and oxidative phosphorylation during cellular respiration.

Explanation:

Both photophosphorylation and oxidative phosphorylation (oxphos) are processes cells use to make energy in the form of ATP.

First the similarities:

• in both cases electrons are transferred through a series of membrane proteins
• the electrons provide energy to pump protons (H+) to one side of the membrane
• the protons flow back through a special enzyme (ATP-synthase) which makes ATP

Then the differences:

• when it occurs:
  oxphos occurs during cellular respiration `harr`
  photophosphorylation occurs during photosynthesis
• where it occurs: oxphos occurs inside mitochondria `harr` photophosphorylation occurs inside thylakoids (in chloroplasts)
• energy source: the energy source for oxphos is glucose `harr`
  the energy source for photophosphorylation sunlight.
• electron acceptor: in oxphos the final electron acceptor is molecular oxygen `harr`
  in photophosphorylation the final electron acceptor is NADP+