Explain the process of carbon fixation in C4 plants, including the roles of mesophyll and bundle sheath cells.

Here is the answer to question 2(b): 2. b) Step 1: Explain the initial carbon fixation in C4 plants. In C4 plants, the Calvin cycle is carried out in a two-step process involving two types of cells: mesophyll cells and bundle sheath cells. Carbon dioxide is first fixed in the mesophyll cells by the enzyme PEP carboxylase, which has a high affinity for CO_2 and does not bind O_2. This forms a 4-carbon compound, typically oxaloacetate. Step 2: Explain the transport and Calvin cycle in bundle sheath cells. The 4-carbon compound is then converted to malate or aspartate and transported to the bundle sheath cells. Inside the bundle sheath cells, the 4-carbon compound is decarboxylated, releasing CO_2. This creates a high concentration of CO_2 around RuBisCO, allowing the Calvin cycle to proceed efficiently with minimal photorespiration. The CO_2 is then fixed by RuBisCO into sugars via the standard Calvin cycle. Send me the next one 📸