Definition of Photosynthesis
Photosynthesis is the process by which green plants, algae, and some bacteria use sunlight to synthesize foods from carbon dioxide and water. It occurs in chloroplasts and produces glucose as an energy source while releasing oxygen as a byproduct. This autotrophic process is essential for converting light energy into chemical energy.
Key Stages and Equation
Photosynthesis consists of two main stages: the light-dependent reactions, which capture sunlight to produce ATP and NADPH in the thylakoid membranes, and the light-independent reactions (Calvin cycle), which use these to fix carbon dioxide into glucose in the stroma. The overall equation is 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.
Practical Example in Plants
In a typical plant like a maple tree, photosynthesis occurs in the leaves during daylight. Chlorophyll absorbs red and blue light wavelengths, initiating electron transport that splits water molecules. This generates oxygen released through stomata and glucose transported to roots or stored as starch, supporting growth and reproduction.
Importance and Applications
Photosynthesis forms the base of most food chains, providing energy for nearly all life forms and producing oxygen vital for respiration. It regulates Earth's carbon cycle, mitigating climate change by sequestering CO₂. Applications include agriculture for crop yield optimization and biofuel production from photosynthetic organisms like algae.