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Photosynthesis. The structure of chloroplast. The spectrum of light. Biochemistry of Photosynthesis. BACKGROUND. The equation of photosynthesis : Carbon dioxide+ Light + Water Sugar + Oxygen + water What’s missing in the equation?.
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BACKGROUND • The equation of photosynthesis : Carbon dioxide+ Light + Water Sugar + Oxygen + water • What’s missing in the equation?
First stage of photosynthesis • Light reaction. • Light energy is changed into electrical energy and then into chemical energy • The energy is stored in the form of ATP and NADPH2 • Occurs in the Grana • Raw material: water • waste products : oxygen Occurs in ?
Second stage of photosynthesis • Dark reaction(Calvin cycle) • The number of PGA (amino acids + fatty acids) and PGAL (glucose + glycerol) is increased by carbon fixation so that some of them are changed into sugars, amino acids and lipids • Some of the PGA and PGAL go back into the Calvin cycle • Occurs in the stroma Occurs in ?
SUMMARY OF LIGHT REACTION Sunlight Chlorophyll Electron(excited) non-cyclic ADP + P ADP + P = ATP = ATP + electron NADP + H = NADPH • cyclic
Cyclic photophosphorylation Sunlight Chlorophyll(Mg) CYCLIC PHOTO- PHOSPHORYLATION electron(excited) ADP + P = ATP + electron
Non-cyclic photophosphorylation Sunlight Chlorophyll (Mg) electron(excited) NON-CYCLIC PHOTO- PHOSPHORYLATION ADP + P = ATP AND NADP + H = NAPDH2 water = 2H+ + electron + oxygen
THINGS TO REMEMBER • Answer the following questions on a piece of paper • 1. Photosynthesis is associated with an organelle known as the (1) • 2. Important products, (2) & (3), are produced in the light reaction • 3. Wastes, (4), are produced during the light reaction
THINGS TO REMEMBER • 4. The hydrogen used for the light reaction comes from (5) in a process called (6). • 5. What is meant by excited electron(7)? • 6. Where, in the chloroplast, does light reaction occur? (8)
WHAT’S THE SCORE! • 1. chloroplast 2. & 3. ATP/NADPH • 4. O2 5. water • 6. photolysis 7. high energy level • 8. grana
DARK REACTION (Calvin cycle) • increases the number of PGA & PGAL ATP & NADPH(energy & H source) PGAL(3C) PGA(3-C) (x 2) CO2 6-C (x 1) RuBP(5-C) (x 1)
Products of photosynthesis :PGA & PGAL • PGA amino acids & fatty acids • PGAL glucose & glycerols • Fatty acids + glycerols lipids
THINGS TO REMEMBER • Answer the following questions • 1. In the dark reaction, the carbon dioxide is first added to (10), and the resultant molecule is split to form two molecules of (11), the first stable product of the dark reaction
THINGS TO REMEMBER • 2. The first carbohydrate form after the fixation of carbon is(12), and it results from the reduction of (13) by the use of (14) formed in the light reaction • 3. The dark reaction takes place in the (16) of the chloroplast.
WHAT’S THE SCORE! • 10. RuBP 11. PGA • 12. PGAL 13. PGA • 14. & 15. H+/ATP 16. stroma
Additional information • You can search the Internet for more information • www.ericse.org • http://esg.www.mit.edu:8001/esgbio/7001/main.html
CARBON DIOXIDE + WATER SUGAR + OXYGEN • WHAT’S MISSING IN THE EQUATION ? (10 MARKS) • ANSWER THE QUESTION NOW, IN POINT FORM.