When you hear carbohydrate you probably are thinking of things in the photo on the right. When we talk about carbohydrates in biology we're talking about the molecules and they look a bit different (bottom right).

Carbohydrates are made of carbon, hydrogen, and oxygen. The glucose model shown on the right can also be ring shaped.

Carbohydrates include sugars and starches. Monosaccharides are simple sugars (sugars with 5 or 6 carbon atoms).

Polysaccharides include starches, cellulose and glycogen. Polysaccharides are several simple sugars bonded together. One example is starch, which is a polymer of glucose monomers.

Carbohydrates can be broken down to provide energy for cells.