CAS BI 107 Lecture Notes - Lecture 10: C4 Carbon Fixation, C3 Carbon Fixation, Carbonic Anhydrase

• School: Boston University
• Department: Biology
• Course: CAS BI 107

Document Summary

Metabolisms of c4 and cam plants (other mechanisms of co2 fixation) The stomata play an important role in regulating the plant"s transpiration, which takes precedence over photosynthesis efficiency. In other words, stomatal opening will always vary to preserve the plant"s water and at the expense of photosynthesis if necessary. Some plants, living in more challenging environments than c3 plants, have developed alternatives to overcome these limitations in order to maintain a certain level of photosynthetic activity. It was thought that all chlorophyll-containing plants incorporated co2 and formed only molecules of 3-phosphoglyceric acid, which were then transformed into triose phosphates, in other words, only molecules with 3 carbon atoms. However, studying the metabolism of higher plants living in hot and arid regions, hatch and slak (1970) discovered that the first molecules formed during the day after co2 incorporation were those of 4- carbon decarboxylic acid. Therefore, they concluded that in addition to "c3" plants, there exist "c4" plants (using another cycle).