Why Do Green Plants Need Chlorophyll?

Chlorophyll is the pigment found in plant cells that gives them their green color. Chlorophyll serves the essential role of helping plants to convert light energy into chemical energy.

Photosynthesis

• Most organisms obtain energy by consuming other energy-containing organisms. Plants produce their own energy from sunlight. Carbon dioxide and water -- both of which plants take up -- contain the same atoms as glucose and oxygen. Rearranging carbon dioxide and water into energy-rich sugar takes energy, however. Here, the chlorophyll found inside the chloroplasts in plant cells plays an essential part.

Function

• Pigments absorb light, which they give off as heat, emit as fluorescence or use to trigger a chemical reaction. Chlorophyll associated with proteins inside plant cells serves the latter function. The light absorbed by chlorophyll makes additional electrons available to power chemical reactions, such as converting carbon dioxide and water into sugar and releasing oxygen as a byproduct.

Significance

• Plants can't eat, so chlorophyll helps to provide them with the energy they need for their life processes. Photosynthesis also sustains life higher on the food chain. Most organisms cannot use energy from the sun. Plants convert sunlight into chemical energy that can pass up the food chain, from plants to herbivores to carnivores.