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Bits of Photsynthesis. Plant Physiology Biology UNI 2008. Plant job description. light. sugar. CO 2. O 2. H 2 O. The good stuff?. The good stuff?. CH 2 OPP. OH. HO. OH. O. O. O. OH. HO. HO. O. O. OH. CHO. COOH. HO. O. GGPP. CH 2 OPP. synthase. IPP. Phytoene.
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Bits of Photsynthesis Plant Physiology Biology UNI 2008
Plant job description light sugar CO2 O2 H2O The good stuff? The good stuff?
CH2OPP OH HO OH O O O OH HO HO O O OH CHO COOH HO O GGPP CH2OPP synthase IPP Phytoene desaturase -carotene desaturase -carotene Lycopene -carotene cyclase cyclase hydroxylase hydroxylase Lutein dioxygenase Zeaxanthin OH ketolase epoxidase HO CHO Violaxanthin Retinal Astaxanthin CH2OH dioxygenase Retinol ABA COOH Retinoic Acid Xanthoxin
Chlorophyll fluorescence dumps excess energy from absorbed light Blue light shined on this green tissue, red fluorescence from chlorophyll.
Photosystem geometry Light harvesting complex =Rxn center + Antenna pigs Reaction center e- Antenna Pigments
Shade and sun plants Shade plant Sun plant Genetic control (capacity) and developmental control. May not be able to adjust later.
Photosynthetic electron flow Thylakoid membrane ADP+ Pi H+ ATP NADPH e- e- PS II PS I Coupling factor e- e- O2 H+ 3 H+ H+ H2O split H2O Cytochrome complex Water splitting complex
The PQ “pump” + + stroma - - + + thylakoid membrane from PS II - to PS I - - - PQ: plastoquinone + + interior of thylakoid Used electron power to move protons (charge battery)
Photo High energy compounds Synthesis Real time Harvests light energy Uses harvested energy Balanced photosynthesis
Unbalanced photosynthesis Photo High energy compounds Synthesis Real time bright light produces lots of energy low-capacity biochemical pathways use it slowly Potential for destruction.