Carbohydrates

Carbohydrates are polymers. The monomers that they are made from are monosaccharides, eg glucose, fructose and galactose.
Glucose is a hexose sugar, a monosaccharide with six carbon atoms in each molecule. There are two forms of glucose - alpha and beta glucose.
Monosaccharides are joined together by condensation reactions.
During a condensation reaction, a molecule of water is released and a glycosidic bond forms between the two monosaccharides. A disaccharide is formed when two monosaccharides join together. A polysaccharide is formed when more than two monosaccharides join together.

Disaccharides and polysaccharides are often present in the food we eat so we need to be able to break them down.we have enzymes released by the intestinal epithelium that break down disaccharides and polysaccharides by hydrolysis.

Maltose is hydrolysed by maltase into glucose and glucose.
Sucrose is hydrolysed by sucrase into glucose and fructose.
Lactose is hydrolysed by lactase into glucose and galactose.

Lactose is a sugar found in milk. It's digested by an enzyme called lactase, found in the intestines. If you don't have enough of the enzyme lactase, you won't be able to break down the lactose in milk properly - a condition called lactose intolerance.
Undigested lactose is fermented by bacteria and can cause lots of…