What is the role of carbon dioxide in photosynthesis?

Carbon dioxide (CO₂) is a primary raw material in photosynthesis, serving as the source of carbon for the formation of glucose and other organic compounds in plants.

It is absorbed from the atmosphere through small pores in leaves called stomata.

Role of carbon dioxide in photosynthesis:

1. Source of carbon for glucose formation
CO₂ provides the carbon atoms that are used to build glucose (C₆H₁₂O₆) during the Calvin cycle.

2. Involvement in carbon fixation
In the first step of the Calvin cycle, CO₂ combines with RuBP in the presence of the enzyme RuBisCO, forming intermediate compounds that eventually lead to glucose synthesis.

3. Essential for biomass production
The carbon from CO₂ is used not only to form glucose but also to synthesize other important plant compounds like starch, cellulose, proteins, and lipids.

4. Regulation of photosynthesis rate
The concentration of carbon dioxide directly affects the rate of photosynthesis:

• Low CO₂ levels limit glucose production

• Optimal CO₂ levels increase photosynthetic efficiency

5. Contribution to oxygen release
Although CO₂ is not directly responsible for oxygen production, its role in photosynthesis supports the overall process in which oxygen is released as a by-product.

In simple terms: Carbon dioxide supplies the carbon needed to make glucose, making it essential for food production in plants.