What is the difference between photophosphorylation and oxidative phosphorylation?

Answer 1

Photophosphorylation occurs during photosynthesis and oxidative phosphorylation during cellular respiration.

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+

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Answer 2

Lydia Adams

Oxidative phosphorylation takes place during cellular respiration and involves the transfer of electrons through the electron transport chain, which generates a proton gradient used to drive ATP synthesis. Photophosphorylation occurs during photosynthesis and involves the use of light energy to drive the addition of a phosphate group to ADP, forming ATP.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.