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Photosynthesis

Photosynthesis. Photosynthesis Process that traps light energy & uses it for carbohydrate synthesis or creation. Phototrophs - both plants and bacteria. C. 2 major processes

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Photosynthesis

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  1. Photosynthesis

  2. Photosynthesis • Process that traps light energy & uses it for carbohydrate synthesis or creation. • Phototrophs - both plants and bacteria

  3. C. 2 major processes 1. light rxns (light-dep. rxns): protons from H2O make ATP from ADP and Pi & electrons from H2O reduce NADP+ to NADPH. a. H2O is split H goes to dark rxn

  4. b. ATP: adenosine triphosphate c. ADP: adenosine diphosphate d. NADP+ : nicotinamide adenine dinucleotide phosphate e. NADPH: reduced nicotinamide adenine dinucleotide phosphate

  5. 2. Dark rxns (light-independent rxns): uses NADPH & ATP in carbon update. a. meaning: C from CO2 & H comes from light rxn - CHO which makes glucose

  6. 3. Both can occur during daylight 4. Overall chemical equation: 6H2O + 6CO2 C6H12O6 + 6O2 light

  7. II. Chloroplast

  8. A. Thylakoid Membrane 1. highly folded membrane network a. CO2 diffuses easily across membrane

  9. 2. Site of light dependent rxn that produce NADPH & ATP

  10. B. Stroma 1. Aqueous matrix 2. enzymes breaks down CO2 . Keep C to make CHO 3. site of dark rxn

  11. C. Lumen 1. aqueous space within thylakoid membrane 2. ATP synthesis

  12. D. Grana 1. thylakoid membrane folded into flattened vesicles & stacked

  13. Parts of the chloroplasts Stroma (fluid) Grana- stacks of Thy. Membrane Thylakoid Membrane: sac that contains chlorophyll Lumen (fluid)

  14. E. Chlorophyll – a & b: green 1. Chl a & Chl b 2. absorbs light in violet/blue to orange/red region 3. Reflects green

  15. F. Accessory pigments 1. carotenoids: oranges 2. phycobilins a. phycoerythrin: red b. phycocyanin: blue 3. Xanthophyll: Yellows

  16. III.Light –Dependent Rxns A. Sunlight excites chlorophyll via antenna complexes B. Passes energy to electron C. Electron pass down Electron Transport Chain (ETC) – twice

  17. As electrons “fall” they lose energy • a. Energy trapped in ATP • D. Electron passed to carrier molecule – NADP+ • E. Combine with H ion from H20 – NADPH

  18. 1. Photosystem II a. located in grana & unstacked region b. splits molecules of H2O into 1/2 O2, 2H, and 2 electrons– photolysis

  19. c. ATP made from ADP + Pi

  20. 2. Photosystem I a. unstacked region of T.M. - lumen b. electron falls down ETC & combines with 2H+ from the surrounding medium and NADP+ to produce NADPH + H+.

  21. 3. Z – scheme: PII & PI

  22. IV. Light independent rnxs A. Use C from CO2 to make glucose B. Takes place in the Stroma C. Also known as Calvin Cycle 1. Melvin Calvin

  23. 2. 6 rounds to get 1 glucose a. CO2 ≠ C6H12O6 animation

  24. Let’s Review: Light-dependent reaction also known as light reaction. - Take place in T.M. - Light energy breaks apart H2O. H kept & combines with NADP+ to form NADPH for dark reaction and O given off.

  25. - Electrons fall down ETC and release energy – this energy is trapped in ATP

  26. Next is Light-Independent Reactions also known as the Dark Reaction or Calvin Cycle. -Take place in the stroma -Uses ATP & NADPH made in light rxn

  27. Uses energy from ATP when broken down to ADP & P • takes H from NADPH to combine with CO2 to form CHO: glucose C6H12O6

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