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The upcoming discussion will update you about the differences between photorespiration and aerobic dark respiration.
Photorespiration:
1. It operates only in green photosynthesizing cells of plants.
2. It takes place mostly in C3 plants.
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3. It operates only during day time when the light is present.
4. Here the substrate used is glycolic acid that is obtained from RuBP (a Calvin cycle intermediate) by the activity of RuBP-oxygenase enzyme.
5. Glycolysis, Krebs’ cycle and terminal oxidation are missing.
6. Since phosphorylation is missing here, it does not yield any usable energy in the form of ATP.
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7. The end products are CO2 and PGA.
8. The end products CO2 and PGA are recycled in photosynthesis by entering Calvin cycle.
9. NADH2 is oxidized to NAD.
10. Saturation point is reached at high oxygen concentration.
11. Chloroplasts, peroxisomes and mitochondria are involved in its operation.
12. It helps to maintain carbon economy of plants.
13. It’s rate is highly accelerated between the temperature 25°-35° C.
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14. It is not essential for survival of the plants.
Aerobic Dark Respiration:
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1. It operates in both green as well as non-green cells.
2. It takes place in all the plants animals except anaerobic microbes.
3. It takes place at all the times.
4. The substrates used may be sugars, starch, fats, organic acids or proteins.
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5. It does involve glycolysis, Krebs’ cycle and terminal oxidation.
6. Through substrate and oxidative phosphorylation, it yields usable energy in the form of ATP.
7. Here the end products are CO2 and water.
8. The end products may sometime be recycled in photosynthesis in green cells.
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9. NAD is reduced to NADH2.
10. Saturation point is attained at lower oxygen concentration.
11. Its operation involves cytoplasm matrix of mitochondria.
12. It plays no such role except in the green cells during the day time.
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13. The process is not so sensitive to rise with temperature.
14. It is essential for survival of the organisms (i.e. plant and animal).