Monosaccharides are the only simplest units of carbohydrates and they are the simplest form of sugar. In other words, It is the most basic form of carbohydrates. They are made up of hydrogen, carbon and oxygen atoms. They are the building blocks of more complex carbohydrates i.e., they can join together and form complex carbohydrates.

For example:

i. Monosaccharides form disaccharides.

ii. 3-10 of them form oligosaccharides.

iii. 11 or more of them form polysaccharides.

Monosaccharides are used to produce and store energy. Most organisms create energy by breaking down the monosaccharide glucose and harvesting the energy released from the bonds. Other Monosaccharides are used to form long fibers, which can be used as a form of cellular structure.

Examples of Monosaccharides are glucose, fructose, and galactose.