<P> C fixation is an elaboration of the more common C carbon fixation and is believed to have evolved more recently . C overcomes the tendency of the enzyme RuBisCO to wastefully fix oxygen rather than carbon dioxide in the process of photorespiration . This is achieved by ensuring that RuBisCO works in an environment where there is a lot of carbon dioxide and very little oxygen . CO is shuttled via malate or aspartate from mesophyll cells to bundle - sheath cells . In these bundle - sheath cells CO is released by decarboxylation of the malate . C4 plants use PEP carboxylase to capture more CO in the mesophyll cells . PEP Carboxylase ( 3 carbons ) binds to CO to make oxaloacetic acid ( OAA ) . The OAA then makes malate ( 4 carbons ) . Malate enters bundle sheath cells and releases the CO . These additional steps , however , require more energy in the form of ATP . Using this extra energy , C plants are able to more efficiently fix carbon in drought , high temperatures , and limitations of nitrogen or CO . Since the more common C pathway does not require this extra energy , it is more efficient in the other conditions . </P>
<P> C fixation is an elaboration of the more common C carbon fixation and is believed to have evolved more recently . C overcomes the tendency of the enzyme RuBisCO to wastefully fix oxygen rather than carbon dioxide in the process of photorespiration . This is achieved by ensuring that RuBisCO works in an environment where there is a lot of carbon dioxide and very little oxygen . CO is shuttled via malate or aspartate from mesophyll cells to bundle - sheath cells . In these bundle - sheath cells CO is released by decarboxylation of the malate . C4 plants use PEP carboxylase to capture more CO in the mesophyll cells . PEP Carboxylase ( 3 carbons ) binds to CO to make oxaloacetic acid ( OAA ) . The OAA then makes malate ( 4 carbons ) . Malate enters bundle sheath cells and releases the CO . These additional steps , however , require more energy in the form of ATP . Using this extra energy , C plants are able to more efficiently fix carbon in drought , high temperatures , and limitations of nitrogen or CO . Since the more common C pathway does not require this extra energy , it is more efficient in the other conditions . </P>
where does carbon fixation occur in c4 plants
where does carbon fixation occur in c4 plants
in the mesophyll cells
in the mesophyll cells