What is the site of $${C_3}$$cycle in ${C_3}$ and ${C_4}$ plants?A. In ${C_3}$ plant – Mesophyll cells and $${C_4}$$ plant – Bundle Sheath cellsB. In $${C_3}$$ plant – Bundle Sheath cells and $${C_4}$$ plant – Mesophyll cellsC. In $${C_4}$$ plant – Bundle Sheath cells and $${C_3}$$ plant – Bundle Sheath cellsD. In $${C_3}$$ plant – Mesophyll cells and $${C_4}$$ plant – Mesophyll cells

Question

Vedantu Content Team · Accepted Answer

Hint: Carbon is fixed into three-carbon sugars from carbon dioxide during the $${C_3}$$ cycle of the chemical reactions inside the plants. A single type of chloroplast is involved in it. The $${C_4}$$ cycle is designed to efficiently fix $$C{O_2}$$ at low concentrations and plants that use this cycle are known as $${C_4}$$ plants. First these plants fix carbon dioxide into a four carbon compound $$\left( {{C_4}} \right).$$Two types of chloroplast are involved in this.Complete answer: In the $${C_4}$$ ​plants, photosynthesis takes place in the chloroplast of a thin-walled mesophyll cell and a four-carbon acid is got over by a thick-walled bundle sheath cell where the calvin cycle takes place. In the $${C_3}$$ ​plants, 3-carbon sugar is produced which can easily diffuse into mesophyll cells, and into the stroma of chloroplasts, where the Calvin cycle takes place. Hence, the site of $${C_3}$$ cycle or Calvin cycle in $${C_3}$$ plants are mesophyll cell and in $${C_4}$$ plants are bundle sheath cell (A layer of cells surrounding the vascular bundles in leaves). So, the correct answer for this is option (A)  'In $${C_3}$$ ​plant - mesophyll cell and In $${C_4}$$ ​plant - Bundle sheath cell'.Note: $${C_3}$$ does not have the bundle Sheath cells. In the $${C_4}$$ pathway, the Calvin cycle takes place in the bundle sheath cells. Six turns taken by the calvin cycle to fix 6 carbon atoms from carbon dioxide. These six turns require energy input for 12 AATP and 12 NADPH mol. in reduction.

Repeaters Course for NEET 2022 - 23