1. 6-1 Notes: Light Reactions

2.  6CO2 + 6H2O → →→→→C6H12O6 (sugar)+ 6O2

3. Chloroplast Parts
Thylakoid: Flattened sacs within the chloroplast. Stacks of thylakoids are called grana.
Thylakoid membrane contains:
chlorophyll molecules
electron transport chain
ATP synthase
Stroma: The liquid area surrounding the thylakoids inside the chloroplast.

4. Light Reaction First stage of photosynthesis Main point:
Absorb light energy and water
Converted to chemical energy ATP and NADPH
Produces oxygen

5. Step 1: Absorb Light
Light reactions begin by Chlorophyll absorbing light.
Chlorophyll a – Pigment that absorbs light energy, some blues and lots of reds. Located in thylakoid membrane

7. Step 2: Move e- down electron transport chain
Electron Transport Chain: group of proteins embedded in thylakoid membrane
Light excites e- and sends them down the electron transport chain (ETC)
This moves Protons (H+) into the thylakoid

9. Step 3: Chemiosmosis ATP Synthease: enzyme at end of ETC
H+ pass through ATP Synthase spinning it.
This powers the conversion of ADP to ATP (which will be used in the Calvin Cycle)

10. Replacing the Electron in Photosystems
Water splits which donates electrons needed to refresh photosystem II.
This Creates Oxygen gas which diffuses out of cell

12. Summary Reactants Products Chlorophyll absorbs light
Electrons move down the ETC pulling H+ into thylakoid
3. Protons (H+) move through enzyme at end of ETC spinning it converting ADP to ATP
4. E- are replaced by the splitting of H2O
This creates O2 gas

13. Create and fill in this chart in your Notes
Reaction
Location
Reactants
Products
Light Reaction
Sunlight
H2O (Water)
O2 (oxygen)
ATP
Thylakoid