1. PHOTOSYNTHESIS USES LIGHT ENERGY TO MAKE FOOD

2. PHOTOSYNTHESIS Process that converts light energy to chemical energy Occurs in chloroplasts of green plants

3. CHLOROPLASTS Most are located in leaves— major site of photosynthesis Contain pigment called chlorophyll Gives chloroplasts their green color

4. CHLOROPLAST STRUCTURE Enclosed by two membranes Inner membrane encloses a thick fluid called stroma Disk-shaped sacs called thylakoids are suspended in stroma Granum: stack of thylakoids

5. CHLOROPLAST STRUCTURE

6. PHOTOSYNTHESIS EQUATION sunlight 6 CO 2 + 6 H 2 O  C 6 H 12 O 6 + 6 O 2 sunlight 6 carbon dioxide + 6 water  glucose + 6 oxygen Occurs in two main stages: 1. light reactions 2. Calvin cycle

7. CHLOROPLAST STRUCTURE ORGANIZES PHOTOSYNTHESIS Reactions take place in different areas of chloroplast: Light reactions occur in thylakoid membranes Calvin cycle occurs in the stroma

9. PHOTOSYNTHESIS and CELLULAR RESPIRATION Photosynthesis Equation: sunlight 6CO 2 + 6 H 2 O  C 6 H 12 O 6 + 6 O 2 sunlight 6 Carbon Dioxide + 6 Water  Glucose + 6 Oxygen Cellular Respiration Equation: C 6 H 12 O 6 + 6 O 2  6 CO 2 + 6 H 2 O + ATP Glucose + 6 Oxygen  6 Carbon Dioxide + 6 Water

10. LIGHT REACTIONS Convert energy in sunlight to chemical energy in steps Chlorophyll molecules capture light energy ( units called photons ) Captured energy is used to split water molecules  photolysis H 2 O  O 2 and H + ions produced

11. LIGHT REACTIONS O 2 escapes from leaf as waste product H + bonds to NADP + (electron carrier molecule) forming NADPH NADPH moves to stroma ATP is produced by light energy

12. THE CALVIN CYCLE ATP from light reactions provides energy to make glucose

13. THE CALVIN CYCLE Calvin cycle reactions are also called the light-independent or dark reactions ( can occur without direct light ) Cannot continue indefinitely without two inputs supplied by light reactions: 1. ATP 2. NADPH

14. THE LIGHT REACTIONS CONVERT LIGHT ENERGY TO CHEMICAL ENERGY

15. LIGHT ENERGY & PIGMENTS Visible light: part of the electromagnetic spectrum our eyes detect as different colors  ROY G BIV Pigments: chemicals that absorb, transmit, or reflect different wavelengths of light

17. What you need to know about the light reactions Occur on thylakoid membranes Get energy from photons of light Reactants: H 2 O, light End products: O 2, NADPH, ATP

18. What you need to know about the light reactions Destination of end products: ATP and NADPH go to stroma (Calvin cycle) O 2 leaves as waste product

19. THE CALVIN CYCLE (Light Independent reactions): MAKES SUGAR FROM CARBON DIOXIDE

20. What you need to know about the Calvin cycle What are the reactants? 1. RuBP 2. NADPH 3. ATP 4. CO 2

21. CALVIN CYCLE What are the end products? - 3-carbon sugar G3P  used by plant cells to produce more complex carbohydrates - glucose - starch - cellulose

22. CALVIN CYCLE Where does energy for Calvin cycle come from? - ATP produced in light reactions Where does the Calvin cycle occur? - stroma of chloroplast

23. SUMMARY OF PHOTOSYNTHESIS