How do c4 plants differ from c3 plants?

How do CAM plants differ from both C3 and C4 plants?

• need it for tom. thanks anyway!!!!!!!!

• Answer:

  CAM plants (which stands for Crassulacean Acid Metabolism, in case you're interested), differ from C3 and C4 plants because they open their stomata and perform carbon fixation at night. Because these plants live in extremely dry environments, they have to keep their stomata closed during the day or they risk losing too much water via transpiration. However, with the stomata closed, they can't get CO2 from the atmosphere. So, CAM plants open their stomata at night and use an enzyme called PEP carboxylase to fix CO2 to a three-carbon molecule called, you guessed it, PEP (for phosphoenolpyruvate). Upon gaining that extra carbon atom, the 3-carbon PEP molecule becomes a four-carbon molecule called OAA (oxaloacetic acid), which is then converted to another four-carbon molecule (malate) and stored in the mesophyll cells' vacuoles until daybreak. Then, the stomata are closed and the malate is changed back to 3-carbon PEP, releasing its extra carbon as CO2 in the process. Rubisco fixes the CO2 with RuBP (ribulose bisphosphate), forming PGA (phosphoglycerate), and the rest of the Calvin-Benson cycle you know. I assume. I hope that helps. Good luck!