Unit 2.1 Topic 2

Carbohydrates 1: simple sugars.

Carbohydrates make up about 10% of the organic matter of a cell. The functions of carbohydrates in organisms include:

• An energy source - released form glucose during respiration.
• An energy store - e.g. starch.
• And for structure - e.g cellulose.

Some carbohydrates also form part of larger molecules, (e.g. Nucleic acids, gylcolipids.)

Carbohydrates contain the elements carbon, hydrogen and oxygen. The term carbohydrate essentially means 'hydrated carbon'. For every carbon present in a carbohydrate, the equivalent of a water molecule is present.

The simplest carbohydrates are called the monosaccharides. These are the monomers (basic units) of carbohydrates. All larger carbohydrates are made by joining monosaccharides together.

There are a number of different monosaccharides, containing between three and six carbon atoms. They all have very similar properties - they:

• are soluble in water,
• are sweet tasting,
• and they form crystals.

The monosaccharides are…