Photosynthesis

1. Photosynthesis Energy for Life Ⓒ Richard Mayberry

2. Two Stages: Light Phase & Dark Phase

3. The Light Reactions

4. Light Energy Light Energy from the sun powers photosynthesis. Light Phase

5. Light Energy Chlorophyll Coated Thylakoid Disks in Grana Light Phase This Energy enters the chloroplasts of plant cells.

6. Light Energy Chlorophyll Coated Thylakoid Disks in Grana Light Phase Chlorophyll converts light to chemical energy.

7. Breaks Bonds Light Energy O H H O H H Breaks Bonds Chlorophyll Coated Thylakoid Disks in Grana Light Phase Some of this energy breaks bonds in water.

8. Light Energy Chlorophyll Coated Thylakoid Disks in Grana Light Phase O2 O H H O H H Oxygen gas is released by the cell.

9. NADP Light Energy H H NADPH2 NADP Chlorophyll NADPH2 Coated Thylakoid Disks in Grana Light Phase O2 H H Hydrogens are collected by NADP molecules.

10. Light Energy NADP NADPH2 NADP NADPH2 ADP ADP ADP ADP P P P P O2 O2 H H H H Chlorophyll Coated Thylakoid Disks in Grana Some of the energy makes ATP molecules by bonding ADP and Phosphate. Light Phase

11. The Dark Reactions

12. CO2 RuBP Unstable 6-Carbon Sugar CO2 combines with RuBP to form a 6-carbon sugar. Dark Phase

13. PGA PGA RuBP Unstable 6-Carbon Sugar CO2 The sugar splits into two PGA molecules. Dark Phase

14. ATP ATP ADP ADP PGA RuBP Unstable 6-Carbon Sugar CO2 PGA ATP gives a phosphate to PGA. Dark Phase

15. ATP ATP ADP ADP PGA~P PGA RuBP Unstable 6-Carbon Sugar CO2 PGA PGA~P PGA~P has extra energy for the next step. Dark Phase

16. ATP ATP P ADP ADP P PGA~P PGA RuBP Unstable 6-Carbon Sugar CO2 PGA PGA~P Removing the phosphate releases energy. Dark Phase

17. NADP NADP ATP ATP NADPH2 NADPH2 ADP ADP PGA~P PGA RuBP P Unstable 6-Carbon Sugar CO2 PGA PGA~P P The energy helps NADPH add hydrogen to the PGA. Dark Phase

18. NADP NADP ATP ATP NADPH2 NADPH2 PGAL ADP ADP PGAL PGA~P PGA RuBP P Unstable 6-Carbon Sugar CO2 PGA PGA~P P This results in production of PGAL molecules. Dark Phase

19. The plant has: 3 "Options" for PGAL

20. To Cytoplasm Respiration PGAL PGAL Send both PGAL’s out for immediate respiration. Dark Phase

21. or

22. ATP ADP P P ATP ADP PGAL GLUCOSE PGAL Combine 2 PGAL’s and remove the phosphates to make Glucose. Dark Phase

23. or

24. RuBP CH2O H2O Calvin Cycle PGAL PGAL Combine 2 PGAL’s and split into multiple products. Dark Phase

25. The Calvin Cycle is the most efficient as it "recycles" everything except the water and carbon dioxide

26. X 6 C6H12O6 GLUCOSE Calvin Cycle PGAL RuBP CH2O PGAL H2O Six Calvin Cycles produce enough carbohydrate to make molecule of glucose

27. Photosynthetic energy from the Sun . . . . . . passes up the food chain to all living things.