Photosynthesis occurs in the chloroplasts of plant cells, which contain stacks of thylakoids where the light-dependent and light-independent reactions take place. Light energy is absorbed by pigments like chlorophyll and carotenoids in the thylakoids, causing electrons to be transferred between photosystems and pumped across the membrane, generating a proton gradient used by ATP synthase to make ATP and ultimately sugars from carbon dioxide in the Calvin cycle.

1. Photosynthesis

2. Photosynthesis Light absorption takes place in the chloroplasts Double membrane bound Stacks of thyakaloids are called grana and suspended in a fluid called stroma (CD) Three major pigments Chlorophyll A Chlorophyll B Carotenoid

3. Electron Transport Pigment clusters called photosystems (CD). Photosystem I Photosystem II

4. Steps Light hits the thylakoid, electrons are excited and water is split Electron enter the Electron Transport Chain H+ ions are pumped into the thylakoid

5. Steps 4. Light re-excites electrons at photosystem 1. 5. ATP and NADPH are both made.

7. Chemiosmosis ETC’s role ATP Synthase (ppt)

8. Calvin Cycle Carbon fixation Dark reaction issues Stomata

9. Alternative Pathways Stomata issues resolved C4 CAM