Definition of carbohydrate: a molecule that consists of carbon, hydrogen and oxygen atoms, usually with a C:H:O ratio of 1:2:1.

A carbohydrate that contains 2 monosaccharide units it’s called a disaccharide; if 3 to 10 units it’s called a oligosaccharide; if more than 10 it’s called a polysaccharide.

monosaccharide

Monosaccharides (also simple sugars) are the simplest units of carbohydrates.

They are colorless, water-soluble and crystalline shaped solids.

Monosaccharides include:

  • glucose
  • fructose
  • galactose

polysaccharide

A polysaccharide is a long-chain polymer composed of more than 10 monosaccharides.

Polysaccharides can have distinct properties from their monomers - they can be amorphous or insoluble in water.

Storage polysaccharides are common storage methods of energy. They can be broken down for converting into usable energy.

  • starch
  • glycogen
  • galactogen
  • inulin

Structural polysaccharides cannot be metabolized by most organisms. For example:

  • cellulose
  • chitin
  • pectin