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• The role of plants
• Types of carbohydrates

Carbohydrates are compounds composed of carbon, hydrogen, and oxygen. The carbohydrate group includes sugars, starches, and cellulose. Sugars and starches provide organisms with energy for cell functions, and cellulose is a fibrous substance making up plant cell walls.

The role of plants

Carbohydrates are produced by green plants through a process known as photosynthesis. In photosynthesis, a pigment called chlorophyll (pronounced KLOR-uh-fill) in the leaves of plants absorbs light energy from the Sun. Plants use this light energy to convert water and carbon dioxide from the environment into glucose and oxygen. Some glucose is used to form the more complex carbohydrate cellulose, the main structural component of plant cell walls. Some is used to provide immediate...