Question

What is needed for carbon fixation?

Answer 1

Carbon Fixation:

1. It is the process of conversion of inorganic carbon from the environment into organic compounds by plants.
2. Carbon Fixation occurs by C₃ or C₄ or CAM pathways. In all three pathways, there is a need of carbon dioxide.

C₃ or Calvin Pathway:

1. This cycle can effectively take place at low temperatures of 15-25°C.
2. Ribulose-1, 5-biphosphate, is the first acceptor molecule of carbon dioxide in this pathway.
3. This occurs in mesophyll cells.
4. RuBP carboxylase enzyme is needed.
5. 12 NADPH and 18 ATP are required for fixing atmospheric carbon to glucose.

C₄ Pathway:

1. PEP carboxylase is a primary acceptor of the carbon dioxide, and RuBP carboxylase found in bundle sheath cells is also needed for the conversion.
2. Mesophyll cells and bundle sheath cells are required.
3. 12 molecules of NADPH and 30 molecules of ATP are needed.

CAM:

1. The RuBP carboxylase enzyme is needed during the daytime, and PEP carboxylase is needed at the night.
2. 39 molecules of ATP and 12 molecules of NADPH are needed for the formation of glucose.

Therefore, carbon fixation requires Carbon dioxide, an acceptor molecule of carbon dioxide, NADPH and ATP.