C3 photosynthesis

C3 photosynthesis is the most common photosynthetic pathway used by plants to convert light and water into chemical energy. Named for the three-carbon compound (3-carbon molecule) that forms as the first stable product, it powers roughly 85% of Earth's plants—from grasses to trees to most crops.

The process unfolds in two stages. During the light-dependent reactions in the chloroplast, light energy splits water molecules and energizes electrons. In the light-independent reactions (the Calvin cycle), plants use that energy to fix Carbon dioxide from the air, building sugars through a series of enzyme-catalyzed steps.

C3 photosynthesis is elegant but inefficient in hot, dry conditions—plants lose water through stomatal pores while gathering CO₂. This vulnerability shaped agricultural strategy and climate resilience concerns in the Anthropocene. By contrast, C4 photosynthesis and CAM photosynthesis evolved as specialized alternatives in arid and tropical zones, using energy-costly but water-sparing tricks.

Understanding C3 pathways matters for genetic improvement of crops, predicting how ecosystems respond to Climate change, and designing synthetic biology systems.

Related

C4 photosynthesis, CAM photosynthesis, Calvin cycle, Chloroplast, Photosynthesis, Plant physiology, Stomata