The alternative pathways of photosynthesis using the C4 or CAM systems are said to be compromises. Why?
A) Each one minimizes both water loss and rate of photosynthesis.
B) C4 compromises on water loss and CAM compromises on photorespiration.
C) Both minimize photorespiration but expend more ATP during carbon fixation.
D) CAM plants allow more water loss, and C4 plants allow less CO2 into the plant.
E) C4 plants allow less water loss, but CAM plants allow more water loss.

Question

Quizplus · Accepted Answer

C4 and CAM pathways both reduce photorespiration, which is a wasteful process where oxygen is fixed instead of carbon dioxide. However, they do so at the cost of requiring more ATP to fix carbon, making them compromises between energy expenditure and efficiency in carbon fixation.

The Alternative Pathways of Photosynthesis Using the C4 or CAM