AP BIOLOGY

Detailed explanation-1: -CO2 is taken up at night-time and stored in the vacuole as malic acid, which is decarboxylated in the light behind closed stomata and CO2 is released for fixation by rubisco in the chloroplast. The closed stomata through the day help CAM plants to maintain water.

Detailed explanation-2: -CAM plants temporally separate carbon fixation and the Calvin cycle. Carbon dioxide diffuses into leaves during the night (when stomata are open) and is fixed into oxaloacetate by PEP carboxylase, which attaches the carbon dioxide to the three-carbon molecule PEP.

Detailed explanation-3: -CAM plants take up carbon dioxide at night but they cannot complete the light-mediated steps of photosynthesis. Instead they produce malic acid that is later used as a substrate to complete the C3 pathway when light is available. CAM plants, under favorable conditions, can switch to using only the C3 pathway.

Detailed explanation-4: -During the night, a plant employing CAM has its stomata open, allowing CO2 to enter and be fixed as organic acids that are stored in vacuoles.

Detailed explanation-5: -Crassulacean Acid Metabolism (CAM) Photosynthesis In this pathway, stomata open at night, which allows CO2 to diffuse into the leaf to be combined with PEP and form malate. This acid is then stored in large central vacuoles until daytime. During the day, malate is released from the vacuoles and decarboxylated.