If a C4 plant needs to fix 5CO2; then how many ATP molecules does it used in its bundle sheath cells to do so-
In C4 plants, the fixation of CO2 into oxaloacetate (OAA)
and the Calvin cycle are separated in space, that is operating in different
types of cells. This fixation into OAA takes place in mesophyll cell and Calvin
cycle takes place in bundle sheath cell (Kranz anatomy is present in leaves of
C4 plants). C4 plants grow generally at areas with high light intensity and
high temperature.
The energy cost of this assimilation of CO2 is greater in C4
plants than in C3 plants. For the PEP carboxylase reaction in C4 pathway, 2
high energy phosphate bonds of ATP are used for assimilating 1 CO2 molecule.
This CO2 molecule will be later fixed through Calvin cycle in mesophyll cell
for which 3 ATP molecules and 2 NADPH molecules will be used.
Hence, to fix 5CO2, 10ATP molecules needed.
In C4 plants, the fixation of CO2 into oxaloacetate (OAA) and the Calvin cycle are separated in space, that is operating in different types of cells. This fixation into OAA takes place in mesophyll cell and Calvin cycle takes place in bundle sheath cell (Kranz anatomy is present in leaves of C4 plants). C4 plants grow generally at areas with high light intensity and high temperature.
The energy cost of this assimilation of CO2 is greater in C4 plants than in C3 plants. For the PEP carboxylase reaction in C4 pathway, 2 high energy phosphate bonds of ATP are used for assimilating 1 CO2 molecule. This CO2 molecule will be later fixed through Calvin cycle in mesophyll cell for which 3 ATP molecules and 2 NADPH molecules will be used.
Hence, to fix 5CO2, 10ATP molecules needed.
