Botany - Photosynthesis in Higher Plants Question with Solution | TestHub

${\mathrm{C}}_4$ photosynthetic pathway is more efficient than ${\mathrm{C}}_3$ pathway as ${\mathrm{C}}_4$ plants can pick up ${\mathrm{CO}}_2$ even when it is found in low concentration. PEP enzymes shows high affinity for ${\mathrm{CO}}_2.{\mathrm{C}}_4$ plants contain two types of chloroplast (Kranz anatomy) : bundle sheath chloroplast and mesophyll chloroplast. Bundle sheath cells contain Calvin cycle enzymes. Due to high concentration of ${\mathrm{CO}}_2$ in bundle sheath cells, RuBP carboxylase works only for Calvin cycle and not for photorespiration. Photorespiration is a wasteful process as it works to undo the act of photosynthesis in ${\mathrm{C}}_3$ plants. No energy rich compound is produced in this process. When temperature increase more and more photosynthetically fixed carbon is lost by photorespiration thus reducing the efficiency of $C_3$ plants.