PHOTOSYNTHESIS
C 4 PHOTOSYNTHESIS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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fix CO2 into organic acids during the night when temperatures are cooler.
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fix CO2 into by combining it with RuBP in the Calvin cycle.
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obtain CO2 through their roots during the day.
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fix CO2 into organic acids in the mesophyll cells, which do not rely on stomata.
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Detailed explanation-1: -In CAM plants, the stomata in the leaves remain shut during the day to reduce transpiration through evaporation, but open at night to collect carbon dioxide (CO2).
Detailed explanation-2: -In CAM photosynthesis, stomatal behaviour reverses; atmospheric CO2 is fixed at night and stomata are closed during the day. The initial CO2 fixation is performed by the enzyme phosphoenolpyruvate (PEP) carboxylase. CO2 is fixed into 4-carbon compounds, primarily malate, and stored in vacuoles as an acid.
Detailed explanation-3: -Unlike plants in wetter environments, CAM plants absorb and store carbon dioxide through open pores in their leaves at night, when water is less likely to evaporate. During the day, the pores, also called stomata, stay closed while the plant uses sunlight to convert carbon dioxide into energy, minimizing water loss.
Detailed explanation-4: -In CAM plants, carbon dioxide is only gathered at night, when the stomata open. Click for more detail. During the day, the malic acid is converted back to carbon dioxide. With the sun shining, the light reactions can create energy for the Calvin cycle and the carbon dioxide can be converted into sugars.