• To make monosaccharides more suitable for transport, storage and to have less influence on a cell’s?osmolarity, they are bonded together to form disaccharides and polysaccharides
• Disaccharides?and?polysaccharides?are formed when?two hydroxyl?(-OH) groups (on different saccharides) interact to form a strong covalent bond called the?glycosidic?bond (the oxygen link that holds the two molecules together)
• Every glycosidic bond results in?one?water?molecule being?removed, thus glycosidic bonds are formed by condensation

The formation of a glycosidic bond by condensation between two monosaccharides (glucose) to form a disaccharide (maltose)

• Each glycosidic bond is catalysed by enzymes specific to which OH groups are interacting
• As there are many different monosaccharides this results in different types of glycosidic bonds forming (e.g maltose has a α-1,4 glycosidic bond and sucrose has a α-1,2 glycosidic bond)

The formation of a glycosidic bond by condensation between α-glucose and β-fructose to form a disaccharide (sucrose)

The formation of glycosidic bonds to create a polysaccharide (amylopectin)

Types of Glycosidic Bonds Table

• The?glycosidic bond?is broken when?water?is?added?in a?hydrolysis?(meaning ‘hydro’ - with water and ‘lyse’ - to break) reaction
• Disaccharides?and?polysaccharides?are broken down in hydrolysis reactions
• Hydrolytic reactions are catalysed by enzymes, these are different to those present in condensation reactions
• Examples of hydrolytic reactions include the digestion of food in the alimentary tract and the breakdown of stored carbohydrates in muscle and liver cells for use in cellular respiration

Glycosidic bonds are broken by the addition of water in a hydrolysis reaction

• Sucrose?is a?non-reducing sugar?which gives a?negative?result in a?Benedict’s test.?When sucrose is heated with?hydrochloric acid?this provides the water that?hydrolyses?the?glycosidic bond?resulting in two monosaccharides that will produce a positive Benedict's test

A molecule of glucose and a molecule of fructose are formed when one molecule of sucrose is hydrolysed; the addition of water to the glycosidic bond breaks it

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