Carbohydrates

Classification of Carbohydrates



Importance of Carbohydrates

1. As main source of energy in a cell.
2. Forming the external skeletons of insects
3. As energy store in animal cells (in the form of starch) and plant cells (in the form of starch).
4. Building cell walls in plant cells
5. It is the important constituent of dietary fibre.

Reducing and Non-Reducing Sugar

1. A reducing sugar is any sugar that can act as a reducing agent.
2. Reducing sugars include glucose, fructose, galactose, lactose, and maltose.

Test for Reducing and Non-Reducing Sugar

1. Benedict's reagent is used to determine if a reducing sugar is present. If it is a reducing sugar, the mixture will turn orange or red.
2. Fehling's solution can also be used for the same purpose.
3. A non-reducing sugar can be tested for in much the same way, but first the non-reducing sugar must be hydrolised by using dilute HCL Hydrochloric acid. Then neutralised. Then heat gently with Benedicts Solution, a positive result will show brick red.