A-level Biology [AQA]

Carbohydrates

Monosaccharides are the monomers of carbohydrates.
common monosacharides:

glucose ,fructose ,galactose

monosaccharides are joined together by glycosidic bonds formed by condensation reactions to form disaccharides. This releases a molecule of water.

polysaccharides

glycogen and starch are both formed by the condensation of alpha glucose

cellulose is formed by the condensation of beta glucose

starch

stores energy in plants and is a mexture of two ppolysaccharides called amylopectin:

Amylose - an unbranched chain of glucose molecules joined by 1, 4 glycosidic bonds and as a result amylose is coiled and thus a very compact molecule storing a lot of energy.

Amylopectin - branched and made up of glucose molecules joined by 1, 4 and 1, 6 glycosidic bonds. Due to the presence of many side branches these can be
acted upon simultaneously by many enzymes and thus broken down to release its energy

Lipids

Lipids are made up of fatty acids.