Metabolic Processes - Photorespiration PDF
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This document provides a summary of photorespiration, C4 photosynthesis, and CAM photosynthesis. It describes the processes, enzymes involved, and their significance.
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# Metabolic Processes - Photorespiration - RuBisCo is the enzyme that catalyzes RuBP + CO2 - This enzyme can also bind to oxygen, causing photorespiration - O2 + RuBP -> a molecule that isn't useful & removes CO2 - RuBP from the Calvin cycle - CO2 is then released rather than fixed - A molecule can...
# Metabolic Processes - Photorespiration - RuBisCo is the enzyme that catalyzes RuBP + CO2 - This enzyme can also bind to oxygen, causing photorespiration - O2 + RuBP -> a molecule that isn't useful & removes CO2 - RuBP from the Calvin cycle - CO2 is then released rather than fixed - A molecule can convert back, but requires lots of ATP ## C4 Photosynthesis 1. Carboxylation - Formation of malate in mesophyll cells 2. Diffusion - Malate diffuses in bundle sheath cells 3. Decarboxylation - of malate (C4) -> pyruvate(C3)+ CO2 4. Transport - Pyruvate -> mesophyll cells. Regeneration of PEP - C4 plants can open stomata less (reducing water loss) - Have less rubisco, lower nitrogen demand (can survive in nutrient poor soil) ## CAM Photosynthesis - Stomata open & CO2 enters - Carboxylation: PEP + CO2 -> malate; PEP carboxylase - Malate is stored in vacuoles - Malate + NADP -> pyruvate + CO2 + NADPH - High concentration of CO2 - Regeneration of PEP: pyruvate + ATP -> PEP + ADP night day
