BIOL 205 Lecture Notes - Lecture 4: Paper Chromatography, Light-Independent Reactions, Carbon Fixation
Document Summary
Light is shine for a very short time (1-2 seconds) Photosynthetic reaction is stopped when the contents is mixed with boiling ethanol. Allows to collect and examine the first product of photosynthesis discovery of 3 carbon sugar (3-phosphoglyceric acid/pga: the founding is further supported by paper chromatography. Synthesis of pga: one c comes from co2, 2 c comes from the cyclic process. Photosynthetic carbon reduction cycle (pcr cycle)/calvin cycle. Some materials are reused: rubp (ribulose-1,5-bis-phosphate carboxylase oxygenase) as an co2 receptor, evidence from steady-state labeling. Steady concentration of rubp and pga with light and sufficient co2. Without light, rubp gets used up, pga accumulates, no atp/nadph production. Without co2, pga gets used up (converted into glyceraldehydes-3-phophate), 8 subunits largest amount of protein on earth. Can fix both co2 (carboxylation) and o2 (photorespiration) Enzyme has higher affinity for co2 than o2 maximize net c gain. 3 process in carbon fixation happen simultaneously: carboxylation. Rubp accepts atmospheric co2 forms two 3-pga: reduction.
