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

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

3. Energy in ATP used to drive the synthesis of organized molecules 6CO 2 + 12 H 2 O + *energy  glucose* *Energy comes from the hydrolysis (breakdown) of ATP. - light independent reactions

4. Photosynthesis 6CO 2 + 12 H 2 O + light  C 6 H 12 O 6 + 6H 2 O + 6O 2

5. Chloroplast 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. Photons: 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: C 6 H 12 O 6 Need H 1. there’s no H in CO 2 2. reducing power - source of attachable H - from H 2 O

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 C 3 photosynthesis