Co2 enters the Calvin cycle producing the first product which is 3-phosphoglycerate. C3 plants have closed stomata on hot and dry days due to losing water. The Calvin cycle is slowed because the Co2 concentration in the leaf air space falls. Rubisco puts O2to RuBP when Co2 moves around. After the product split, a two carbon compound leaves the chloroplast and releases Co2.
C4 Plants:
C4 plant is added to PEP (3 carbon compound) with the help of an enzyme. The left over four carbon compound in the mesophy2 calls of the leaf is moved to bundle sheath cells tightly packed around veins of leaf. C4 is breaks down to release Co2 making concentrations high so that rubisco can get Co2 and start the calvin cycle.
CAM Plants:
In some plants stomatas are closed during the day to reduce extra water loss from transpiration. Desert plants can CAM (crassulacean acid meatobolism) photosynthesis, photosynthesize while stomatas are closed. In CAM photosynthesis, a process similar to C4 photosynthesis, PEP carboxylase is used to fix Co2 to oxaloacatate, but oxaloacetate is changed to malic acid instead of malateand sent to cells vacuole. During the day, malic acid is changed back to oxaloacetate and carbon dioxide is released for photosynthesis. Co2 later then enter the Calvin cycle.
http://wc.pima.edu/Bfiero/tucsonecology/plants/plants_photosynthesis.htm
No comments:
Post a Comment