What are the subunits and functions of carbohydrates?

The fundamental building blocks of carbohydrates are called monosaccharides, such as glucose, which are typically broken down by our metabolism to create chemical energy (ATP) and keep our cells functioning.

Disaccharides, which are actually the carbohydrates we eat and are composed of two monosaccharides bonded together, are the most prevalent form of "sugar" found in nature as opposed to monosaccharides; lactose, which is found in milk, and saccharose, which is found in beets, are two examples of disaccharides broken down into monosaccharides in order to produce energy.

Long chains of monosaccharides, or polysaccharides, are much more stable than mono- or dissaccharides and can serve a variety of purposes. Structurally, polysaccharides can be used for things like cellulose, which is found in plant leaves and stems, and chitin, which is found in insect carapaces. Structurally, polysaccharides can also be used for things like long-term energy storage, like starch and glycogen in animals, both of which can be broken down by the organism to release energy.

The subunits of carbohydrates are monosaccharides, such as glucose, fructose, and galactose. Carbohydrates function as a source of energy, structural components in cells, and play a role in cell signaling and recognition.