CAM plants fix CO2 at night using which enzyme, storing as malate; stomata are open at night to reduce water loss. Which statement describes this adaptation?

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Multiple Choice

CAM plants fix CO2 at night using which enzyme, storing as malate; stomata are open at night to reduce water loss. Which statement describes this adaptation?

CAM plants separate CO2 uptake from the Calvin cycle by timing: they open their stomata at night to take in CO2 and fix it with PEP carboxylase, producing oxaloacetate that is reduced to malate and stored in vacuoles. This nocturnal fixation is energy-efficient and minimizes water loss in dry environments. During the day, stomata stay closed, malate is released and converted back to CO2, which is then fixed by Rubisco in the Calvin cycle. So describing the adaptation as fixing CO2 at night with PEP carboxylase captures the distinctive nocturnal CO2 uptake mechanism of CAM plants.

CAM plants separate CO2 uptake from the Calvin cycle by timing: they open their stomata at night to take in CO2 and fix it with PEP carboxylase, producing oxaloacetate that is reduced to malate and stored in vacuoles. This nocturnal fixation is energy-efficient and minimizes water loss in dry environments. During the day, stomata stay closed, malate is released and converted back to CO2, which is then fixed by Rubisco in the Calvin cycle. So describing the adaptation as fixing CO2 at night with PEP carboxylase captures the distinctive nocturnal CO2 uptake mechanism of CAM plants.

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