ESS361H1 Lecture Notes - Lecture 7: Photo-Oxidation Of Polymers, Phosphoenolpyruvate Carboxylase, Crassulacean Acid Metabolism
Document Summary
H2o + co2 + energy = ch2o + o2 :cellular respiration. Photosynthetic inefficiency carbon-fixing enzyme in plants called: rubisco. Rubisco for o2 increases with increasing temperature. High wue: fixes more carbon per molecule of water lost to atmosphere. Calvin cycle occurs in mesophyll cells subject to photorespiration. Pepc= phosphoenolpyruvate carboxylase primary carboxylation occurs in mesophyll cells to produce a c-intermediate (4-chain) C-intermediate actively pumped (requires atp!!!) into bundle sheath cells where it encounters. Cam photosynthesis same biochemistry as c4 pathway but no specialized bundle sheath cells. Pepc fixation is separated from rubisco fixation by time. During night when chance of photorespiration is low, plants open stomata and fix co2 (pepc) During day, plants close stomata and undergo calvin cycle (rubisco-fixation) found in many desert succulenfs and plants growing in very arid regions: also includes epiphytes ( air plants ) Factors affecting photosynthesis (in c3 plants: light. Light compensation point: minimum light level necessary to offset negative carbon balance.
