Light reactions happens in the thylakoid membrane, and the calvin cycle happens in the stroma. What happens to water molecules in the light reactions? It's broken apart and the electrons go to photosystem II. ... Then they pump H+ into the thylakoids, and are used to make ATP out of ADP.
The animal cells get the organic compounds by eating plants. The only form of energy a cell can use is a molecule called adenosine triphosphate (ATP). Chemical energy is stored in the bonds that hold the molecule together.
