What are monosaccharides?

According to the size, monosaccharides are classified into three major groups: monosaccharides, oligosaccharides, and polysaccharides.

Monosaccharides are carbohydrates that cannot be further hydrolysed to simpler units having the basic formula Cn(H2O)n, where n=3 or more. Monosaccharides can by combined through glycosidic bonds to form larger carbohydrates, known as oligosaccharides or polysaccharides.

Monosaccharides, the simplest type of carbohydrates, are often called simple sugars (sucrose), containing three to seven carbon atoms, and serve as the building blocks for larger molecules. Since they have multiple asymmetric centers, many types of isoforms are possible, including enantiomers, diastereoisomers, and epimers.

There are 3 monosaccharides: glucose, fructose, galactose.

Fructose (or levulose) is a simple sugar (monosaccharide) found in many foods. It is a constituent of disaccharides sucrose. It can be covered into glucose in the liver. Honey, tree fruits, berries, melons and some root vegetables, such as beets, sweet potatoes, parsnips and onions, contain fructose, usually in combination with sucrose and glucose.

Glucose (C6H12O6) is one of the most common monosaccharides in nature, used by nearly every form of life. It is one of the most important monosaccharides, which is synthesized during photosynthesis and serves as the ‘fuel’ and source of energy, stored as a polymer glycogen in animals and as starch in plants.

Galactose binds to glucose to form the disaccharide lactose. It can be converted into glucose in the liver. Galactose widely distributed in plant gums and pectins and is found in milk sugar (the disaccharide lactose).

The last large class of carbohydrates are polysaccharides, commonly known as glycans. They are complex carbohydrates composed of large number of monosaccharides linked together covalently by glycosidic bonds, which can be linked linearly in a chain or branch laterally forming complex polymers.
What are monosaccharides?