Carbohydrates
• Carbohydrates are the main source of energy of the organism.
•
Carbohydrates are represented by the simple sugars, the disaccharides, and the
polysaccharides
Carbohydrates are of three classes:
1- Simple sugar (Monosaccharides) : that are made up of a simple molecule of sugar of
formula : C6 H12 O6
➢ Fructose
➢ Glucose
2- Double sugar (Disaccharides): Made up of two molecules of simple sugar.
➢ Sucrose: made up of one molecule of glucose and a molecule of fructose
➢ Maltose: made up of two molecules of glucose
➢ Lactose: made up of one molecule of glucose and a molecule of galactose.
3- Complex sugar (Polysaccharides): is a polymer of monosaccharides.
➢ Starch: is a complex sugar made up of a large number of molecules of glucose
➢ Cellulose: It is also a polymer of glucose. It is the main substance in the walls of plant
cells, helping plants to remain stiff and upright. Humans cannot digest cellulose, but it is
important in the diet as fiber.
Monosaccharides
Glucose
Fructose
Carbohydrates
Disaccharides
Sucrose
Maltose
Polysaccharides
Lactose
Starch
Cellulose