1. 6-1 Notes: Light Reactions

2. Parts of the Chloroplast
Thylakoid Membrane: Flattened sacs within the chloroplast. Stacks of thylakoids are called grana
Stroma: The liquid surrounding the thylakoids

3. Parts of the Chloroplast
Photosystem: Protein full of chlorophyll a
Located in the thylakoid membrane.

4. Parts of the Chloroplast
Electron Transport Chain (ETC): made up of multiple proteins embedded in the thylakoid membrane.
Transports electrons

6. Photosynthesis occurs in two parts
LIGHT REACTIONS:
Make ATP and e- carrier
CALVIN CYCLE:
Uses the ATP and e- carrier to make carbohydrates

7.  6CO2 + 6H2O → →→→→C6H12O6 (sugar)+ 6O2

8. Light Reaction First stage of photosynthesis Main point:
Absorb light energy and convert to chemical energy (ATP)
Splits H2O to Produces O2
GOAL: make ATP to power the Calvin Cycle
6CO2 + 6H2O → →→→→C6H12O6 (sugar)+ 6O2

9. Light and Pigments
Light: Visible light includes the colors of the rainbow
Pigments: Compounds that absorb specific colors of light. Absorbed colors are not visible.
Ex: Markers and dyes have pigments

10. Chloroplast Pigments Chlorophyll a – Pigment that absorbs light energy
Absorbs reds and blues
Located in photosystem in thylakoid membrane.
Chloroplast are green because they don’t absorb green!

11. Chloroplast Pigments 2. Chlorophyll b
Absorbs lots of blues and some reds
3. Carotenoids
Three pigments (Orange, Brown, and Yellow) that focus on absorbing blues and greens
These colors are seen in the fall and in vegetables

12. Step 1: Light Absorption
Chlorophyll a Absorbs light
H2O is split and an electron picks up the light energy
Oxygen is a waste product and diffuses out of the cell

13. Step 2: ETC
Electrons (e-) from Photosystems move along ETC and attach to an e- carrier called NADP+ to form NADPH
NADPH is used later on!

14. Step 3: Chemiosmosis
Many protons (H+) on one side of thylakoid membrane
H+ move from high to low CONC and pass through ATP synthase (enzyme)
ATP synthase converts ADP + P  ATP
ATP is used later on too!

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