1. Light Reactions & Pigments pp. 116-124
PHOTOSYNTHESIS Part 2
Light Reactions & Pigments pp

2. 6CO2 + 6H2O  6O2 + C6H12O6 sunlight Questions to ask:
Why is photosynthesis important? (provides oxygen for us, and food for plants to become food. Without plants, animals would die off. Without animals, humans would die off)
What part of the plant “does” photosynthesis?
ANS: Chloroplasts

4. Light and Pigments Chloroplasts contain pigments
Pigments absorb specific colors of light
Colors that are absorbed are NOT visible

5. Pigments Chlorophyll a: absorbs reds and blues
Chlorophyll b: absorbs a lot of blue and some red
Carotenoids: absorb blues and greens (colors seen in vegetables and during the fall season)

7. Light Absorption
Clusters of pigments called photosystems absorb light energy
Photosystems are located in the thylakoid membrane

8. Electron Transport Chain
H2O is split by an enzyme
Makes H+ (Protons) and O2
Also excites an electron that starts the electron transport chain

9. Electron Transport Chain
Electrons (e-) from photosystems move down ETC and attach H+ to NADP+ to make NADPH
This NADPH is used later on!

10. Chemiosmosis Makes ATP H+ moves through ATP synthase to make ATP
ATP is used later on too!

11. Photosynthesis - Two Parts
LIGHT REACTIONS:
Make ATP, NADPH, and O2
CALVIN CYCLE:
Uses the ATP and NADPH to make carbohydrates
1. Light absorption (by plant pigments)
2. Electron transport chain (making NADPH)
3. Chemiosmosis (making ATP)

12. Draw and fill in this chart! The bottom half will be filled in tomorrow!
REACTION
LOCATION
REACTANTS
PRODUCTS
LIGHT REACTIONS
Thylakoid
Sunlight
H2O O2
ATP
NADPH

13. Vocab to keep in mind: Pigments Photosystems Light Reactions
Electron Transport Chain
Chemiosmosis