Question

In which cell type initial carboxylation reaction occurs in ${C_3}$ and ${C_4}$ plants?

Answer 1

Hint : ${C_4}$ and ${C_3}$ plants are plants having different ways of fixing carbon. In the C3 plants, the first compound form is of 3 carbon ( Phosphoglyceric acid ) while in C4 plants the first compound is of 4 carbon ( Oxaloacetic acid ) . ${C_3}$ and ${C_4}$ carbon fixation or the Hatch–Slack pathway is one of the three known photosynthetic processes of carbon fixation in plants .

Complete Step By Step Answer:
Plants : The Calvin cycle takes place in the mesophyll cells. The initial carboxylation reaction occurs in the mesophyll cells. A single cell is required for carbon fixation. The primary acceptor of $C{O_2}$ in ${C_3}$ plants are Ribulose 1,5-bisphosphate ( RUBP) . RUBP has 5 carbons . The primary $C{O_2}$ fixation product in the ${C_3}$ cycle is Phosphoglyceric acid ( PGA) . Which is 3 carbon compounds. ${C_3}$ carbon fixation is the most common of the three metabolic pathways for carbon fixation in photosynthesis along with ${C_4}$ and Crassulacean acid metabolism (CAM) . The process converts carbon dioxide and ribose 5 phosphates into two molecules of 3- phosphoglycerate. The reaction occurs in all the plants as the first step of the Calvin cycle.
${C_4}$ plants : The Calvin cycle takes place in the bundle sheath cells. The initial carboxylation reaction occurs in the mesophyll cells. Two cells are required for carbon fixationThe primary acceptor of $C{O_2}$ in ${C_3}$ plants are Phosphoenolpyruvate ( PEP) . PEP has 3 carbons . The primary $C{O_2}$ fixation product in the ${C_4}$ cycle is Oxaloacetic acid ( OAA ) . Which is four-carbon compounds ${C_4}$ carbon fixation or the hatch slack pathway is a photosynthetic process in some plants. It is the first step in extracting carbon from carbon dioxide to be able to use it in sugar and other biomolecules. ${C_4}$ refers to the four-carbon molecule that is the first product of this type of carbon fixation .

Note :
Major difference between ${C_4}$ and ${C_3}$ plants is photorespiration. ${C_3}$ plant undergoes photorespiration also called the ${C_2}$ cycle while ${C_4}$ does not due to the presence of Kranz anatomy.The regions where these crops are grown in are often hot and dry, meaning they could benefit from the energy-saving mechanisms of ${C_4}$ photosynthesis. While ${C_3}$ photosynthesis has more room for improvement .