ENERGY FOR LIFE: Photosynthesis—Turning Sunlight into Food

Plants and some single-celled bacteria and algae, on land and in water, are green because they contain a chemical called chlorophyll. It has an extraordinary ability. Any cell with chlorophyll can capture the light energy from the sun and store it for later use. The energy is stored in the chemical bonds of carbohydrates—sugars and starches. The plant builds the carbohydrates from smaller molecules of water and carbon dioxide.

Organisms that can do photosynthesis are called producers. Organisms that can't do it are either consumers or decomposers. Consumers (including people) and decomposers eat the producers, and use the energy the producers stored for themselves. For example, we eat the plants or we eat the animals that eat the plants. This is how the sun’s energy is passed through the web of life.

The solar energy stored in food provides fuel for our bodies, and for most living organisms. Stored solar energy also provides well over 90% of the fuel used in human agriculture, industry, buildings, and transportation.

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