C3 vs. C4 Photosynthesis: Key Differences Explained

🌱 What is C3 Photosynthesis?

C3 photosynthesis is the most common type of photosynthesis. It involves the direct fixation of carbon dioxide by the enzyme RuBisCO into a three-carbon compound (3-PGA). This process occurs in the mesophyll cells of the plant.

☀️ What is C4 Photosynthesis?

C4 photosynthesis is an adaptation to hot and dry environments. It involves an initial fixation of carbon dioxide in mesophyll cells to form a four-carbon compound (oxaloacetate), which is then transported to bundle sheath cells where carbon dioxide is released and enters the Calvin cycle. This helps to minimize photorespiration.

🔬 C3 vs. C4 Photosynthesis: Key Differences

🔑 Key Takeaways

• 🧪 Efficiency: C4 photosynthesis is more efficient than C3 photosynthesis in hot, dry conditions because it minimizes photorespiration.
• 🌍 Adaptation: C4 plants are adapted to environments with high temperatures, high light intensity, and limited water availability.
• 🧬 Anatomy: The Kranz anatomy in C4 plants, with specialized mesophyll and bundle sheath cells, facilitates the efficient capture and concentration of CO2.
• 💡 RuBisCO: In C3 plants, RuBisCO can react with both $CO_2$ and $O_2$, leading to photorespiration, whereas C4 plants minimize this by concentrating $CO_2$ in bundle sheath cells.
• 🔢 First Products: The initial carbon fixation product differs; C3 plants produce a 3-carbon compound, while C4 plants produce a 4-carbon compound.