Photosynthesis+II

Discuss how C4 and CAM photosynthesis improve upon C3 photosynthesis. Include both advantages and disadvantages of the processes. Describe appropriate leaf anatomy to complete your discussion.
C4 and CAM plants are improvments of the typical C3 plants because of the way that they fix the carbon molecules before entering the Calvin cycle. C3 plants actually decrease ATP and glucose output because it requires ATP, does not produce ATP, and does not produce any sugar (glucose). This seemingly unproductive process called photorespiration is utilized in crops like rice, wheat and soybeans. C4 and CAM plants however adapted and have a more efficient why of producing ATP and sugar. Probably, the most important difference in C3 and C4 plants is the way the leaf is set up. C4 plants have 2 kinds of photosynthesizing cells as opposed to C3's one. The two different types include bundle-sheath cells and mesophyll cells. Bundle-Sheath cells are tightly packed around the vein of a leaf and is the sight of the Calvin Cycle. Mesophyll cells are around the outside of the Bundle-sheath and are less tightly packed. Here, CO2 added to the organic compounds need for the Calvin Cycle. This adaptation has made it possible for C4 plants to live in hot regions with abundant sun. CAM plants carry out a similar process to C4 plants in that the fixation of the organic compound needed for the calvin cycle is made before the actual Calvin Cycle begins. However, instead of fixing the carbon in a completely different cell like C4 plants, CAM plants fix carbon at different times. At night, carbon fixation occours and are stored in the mesophyll cells until the sun comes out and the stomatas closes. At this time, light reactions generate ATP and NADPH to power the Calvin Cycle. (Chelsea 2.23.09 ) C4 and CAM plants incorporate Co2 into a four carbon compounds, where C3 plants produce a three carbon compound (phosphoglycerate) before entering the Calvin Cycle. Plants that use this process are corn, sugarcane, and agriculturally important grasses.(Monica 3.7.09)