ABSTRACT
As an energy source, they are not only broken down, but when there is a surplus, they are stored as starch and glycogen. Therefore, it is important to realise that sugars are involved in a host of metabolic pathways, and not just the provision of energy. Given that energy is locked up in chemical bonds, energy can be extracted from glucose by breaking some of its chemical bonds. Surprisingly, this can be achieved without the use of oxygen. For a sugar to be used as a building block for other molecules such as glycogen or as glycosaminoglycans, it must be firstly activated by attaching it to a nucleotide. Sugar amines or glycosamines are a very important component of polysaccharides known as glycosaminoglycans. The sugar is then carried into the lumen of the endoplasmic reticulum and transferred to the growing oligosaccharide.
