Q.Explain the CAM cycle, and state the key difference between how C4 plants and CAM plants separate the initial CO2-fixation step from the Calvin cycle.

[!TLDR]

CAM separates the two steps by time (night fixation, day Calvin cycle) within one cell; C4 separates them by space (mesophyll vs bundle sheath cells). …

Both CAM and C4 plants perform the same two underlying steps -- initial fixation by PEP carboxylase, and the Calvin cycle by RuBisCO -- but they separate the two steps differently. CAM plants keep both steps in the same single mesophyll cell, separating them in time instead: stomata open at night, allowing CO2 fixation and storage as malic acid in the vacuole; stomata close by day, conserving water, while the stored malic acid is decarboxylated to release CO2 for the Calvin cycle, powered by the daytime light reaction. C4 plants, by contrast, keep both steps running more or less continuously through the day, but separate them spatially between two co …

Contrast the key word for each pathway: CAM = temporal (day vs night) …

Describing CAM as using Kranz anatomy -- Kranz anatomy is specific to C4 plants; CAM plants show …