Plants convert sunlight into energy through a process called photosynthesis. This process occurs mainly in the leaves, within specialized structures called chloroplasts that contain the green pigment chlorophyll, which absorbs sunlight, especially in the blue and red wavelengths
. The process can be summarized in two main stages: 1. Light-dependent reactions:
- Chlorophyll absorbs sunlight, which excites electrons.
- Water molecules are split (photolysis), releasing oxygen (O₂), protons, and electrons.
- The energized electrons move through an electron transport chain, creating a proton gradient that drives the production of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), energy-rich molecules
2. Light-independent reactions (Calvin cycle):
- ATP and NADPH produced in the light reactions are used to convert carbon dioxide (CO₂) from the air into glucose (C₆H₁₂O₆), a sugar that stores chemical energy.
- This process of converting inorganic carbon into organic compounds is called carbon fixation
The overall chemical equation for photosynthesis is:
6CO2+6H2O+light energy→C6H12O6+6O26CO_2+6H_2O+\text{light energy}\rightarrow
C_6H_{12}O_6+6O_26CO2+6H2O+light energy→C6H12O6+6O2 This means plants
take in carbon dioxide and water, use sunlight to produce glucose for energy
and growth, and release oxygen as a byproduct
. In essence, photosynthesis transforms solar energy into chemical energy stored in glucose, which the plant can use immediately or store for later, supporting not only the plant’s life but also the energy needs of other organisms in the ecosystem
