In what process does cross over occur

Crossing over is a biological occurrence that happens during meiosis when the paired homologs, or chromosomes of the same type, are lined up.

Explanation:

The steps of light reactions in order:

1. Electrons move down the electron transport chain, releasing energy

2. ATP uses energy to add a phosphate to ADP forming ATP

3. Electrons from the electron transport chain close to photosystem II replace the elctrons lost in photosystem I

4. A protein in the electron transport chain, pumps H+ ions from the stroma into the thylakoid space

5. Electrons from Photosystem I become energized and escape photosystem I and move down the second electron transport chain.

6. Water is split to replace the electrons in photosystem II

7. H+ ions flow down the concentration gradient through a channel in ATP Synthase, releasing energy in the process

8. At the end of the electron transport chain, the energized electrons and an H+ ion are used to reduce NADP+ to NADPH

9. Light energy is transferred to a chlorophyll reaction center where electrons become energized.

10. Photosystem II receives photons in the form of light energy

11. Electrons move to an electron acceptor in the electron transport chain and electrons in photosystem II are replaced by the splitting of a water molecule

I am pretty sure I got that right! :)