1. Chloroplasts
1. plants (leaves)
2. algae

2. ADP + Pi + energy*  ATP* Energy captured from sunlight
This energy used to drive ATP synthesis
- light reactions
ADP + Pi + energy*  ATP*
*Light energy from the sun

3. Energy in ATP used to drive the synthesis of organized molecules
- light independent reactions
6CO H2O + *energy  glucose*
*Energy comes from the hydrolysis (breakdown) of ATP.

4. Photosynthesis
6CO H2O + light  C6H12O6 + 6H2O + 6O2

5. Structure
1. thylakoids
- chlorophyll pigments in membrane (photosystem)
2. grana
3. stroma

6. Photosystem
1. pigments “capture” photons
2. excites an electron

7. 3. energy of the electron is passed through the system
4. energy transferred to membrane-bound proteins on the thylakoid membrane

8. Electromagnetic spectrum

9. Plants absorb mainly red and blue.
Pigments only absorb photons of particular wavelengths.

10. Pigments are molecules developed for absorbing photons
Retinal
found in the human retina
absorbs light in the “visible spectrum”
Some organismal pigments absorb outside the visible spectrum

11. Chlorophyll
a and b forms
absorb red and blue and reflect green

12. Chlorophyll is extremely efficient at capturing a narrow range of photons.
It excites an electron whose energy is passed through the pigment.

13. Carotenoids - absorb light at different wavelengths than chlorophyll
- absorb blue and green and reflect orange and yellow

16. Making Glucose: C6H12O6 Need H 1. there’s no H in CO2
2. reducing power
- source of attachable H
- from H2O

17. There is a different chlorophyll which absorbs another photon (Photosystem I).
excited electron on H atom transferred to NADP

18. NADPH carries H to growing carbon chain of glucose.
Energy from that electron used to “stick on” H

19. Calvin Cycle
C3 photosynthesis