Photosynthesis. I.Photosynthesis A.Process that traps light energy & uses it for carbohydrate...
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Transcript of Photosynthesis. I.Photosynthesis A.Process that traps light energy & uses it for carbohydrate...
I. Photosynthesis
A.Process that traps light energy & uses it for carbohydrate synthesis or creation.
B.Phototrophs - both plants and bacteria
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
b. ATP: adenosine triphosphatec. ADP: adenosine diphosphated. NADP+ : nicotinamide adenine dinucleotide phosphatee. NADPH: reduced nicotinamide adenine dinucleotide phosphate
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
Parts of the chloroplasts
Grana- stacks of Thy. Membrane
Stroma (fluid)
Thylakoid Membrane: sac that contains chlorophyll
Lumen (fluid)
E. Chlorophyll – a & b: green
1. Chl a & Chl b
2. absorbs light in violet/blue to orange/red region
3. Reflects green
F. Accessory pigments
1. carotenoids: oranges
2. phycobilins
a. phycoerythrin: red
b. phycocyanin: blue
3. Xanthophyll: Yellows
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
1.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
1. Photosystem II
a. located in grana & unstacked region
b. splits molecules of H2O into 1/2 O2, 2H, and 2 electrons – photolysis
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+.
3. Z – scheme: PII & PI
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
2. 6 rounds to get 1 glucose
a. CO2 ≠ C6H12O6
animation
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.
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