BIOL1007 Lecture Notes - Lecture 9: Ribulose, Light-Independent Reactions, Carbon Fixation
19 May 2018
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Explain fixation of carbon dioxide in the Calvin cycle
The Calvin Cycle
Screen clipping taken: 29/09/2017 8:20 PM
RBP and CO2 -> two 3-PGAs
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Carboxylation by rubisco
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Phase 1: Carbon fixation
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Reduction add phosphate, replace with H
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Oxygen from COOH needs to be reduced to generate ADP
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Phase 2: Reduction
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3Cs to 5Cs
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Regeneration of ribulose 5-phosphate
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Phase 3: Regeneration of ribulose
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3 main phases
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Compare carboxylation and oxygenation by Rubisco
Ribulose bis-phosphate carboxylase/oxygenase (so involved in both processes)
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Ribulose bis-phosphate can react with OXYGEN AND CARBON
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Most abundant protein on earth
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Found in chloroplast stroma
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8 large sub-units, gene within chloroplast DNA
8 small subunits, genes within nucleus DNA
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Screen clipping taken: 29/09/2017 8:17 PM
Rubisco
Screen clipping taken: 29/09/2017 8:44 PM
Carboxylation
oxygenation
L9 - photosynthesis II
Friday, 29 September 2017
8:13 PM
Mod 2 Energy Systems and Cells Page 1
Document Summary
Explain fixation of carbon dioxide in the calvin cycle. Oxygen from cooh needs to be reduced to generate adp. Ribulose bis-phosphate carboxylase/oxygenase (so involved in both processes) Ribulose bis-phosphate can react with oxygen and carbon. Mod 2 energy systems and cells page 1. Describe the co-evolution of photosynthesis and the earth"s atmosphere over time. Last 2000 years co2 conc increase exponentially due to humans. Evolution of c4 photosynthesis, occurred when co2 dropped to very low. Produces 4 carbon product in mesophyll cells, then moved over to bundle sheath cells (decarboxylated then go around carbon cycle) Bundle sheath cells - barrier to co2 diffusion leak proof cell, allows co2 conc around rubisco to be very high, increasing photosynthesis so plants don"t starve. Mod 2 energy systems and cells page 2. Predict how photosynthesis might respond to future climates. Energy from electron transport chain drives calvin cycle. C3 plants have shallower response, don"t have carbon concentrating mechanisms around rubisco.
