Question

Difference between C4 and C3 cycle?

Answer 1

Answer:

In C3 cycle, the carbon dioxide fixation takes place only at one place. In C4 cycle, the carbon dioxide fixation takes places twice (first in mesophyll cells, second in bundle sheath cells). Only a single type of chloroplasts is involved in C3 cycle. ... Two types of chloroplasts are involved in C4 cycle.

Answer 2

C4 plants—including maize, sugarcane, and sorghum—avoid photorespiration by using another enzyme called PEP during the first step of carbon fixation. This step takes place in the mesophyll cells that are located close to the stomata where carbon dioxide and oxygen enter the plant. PEP is more attracted to carbon dioxide molecules and is, therefore, much less likely to react with oxygen molecules. PEP fixes carbon dioxide into a four-carbon molecule, called malate, that is transported to the deeper bundle sheath cells that contain Rubisco. The malate is then broken down into a compound that is recycled back into PEP and carbon dioxide that Rubisco fixes into sugars—without having to deal with the oxygen molecules that are abundant in the mesophyll cells.

C3 plants include some of the most important sources of calories all over the world: cowpea, cassava, soybean, and rice. The regions where these crops are grown in are often hot and dry, meaning they could benefit from the energy-saving mechanisms of C4 photosynthesis. While C3 photosynthesis has more room for improvement, our computer models suggest that we can improve both types of photosynthesis to increase crop production.