Carbohydrates-Monosaccharides and Poly/Disaccharides

What is Polymerisation?

Monomers (usually carbon) link to form polymers (long chain of monomers)

Condensation Reaction

Water is removed to combine 2 molecules.

Hydrolysis Reaction

Water is added to break down a polymer into 2 monomers.

Monosaccharide

Sweet soluble substances (CH20) e.g glucose,fructose

What is the structure of an an alpha glucose molecule?

What is the structure of an an beta glucose molecule?

What is the test for reducing sugars?

Benedicts Reagent- alkaline copper sulfate solution that forms a red precipitate when heated with a reducing sugar

-Add 2cm³ of food sample (liquid form)

-Add equal vol of Benedicts Reagent

-Neutralise the solution

-Heat mixture in boiling water bath for 5 mins

How is maltose formed?

Glucose + Glucose

How is sucrose formed?

Glucose + Fructose

How is lactose formed?

Glucose + Galactose

What are the bonds called formed by a condensation reaction?

Glycosidic bonds

Polysacchaides

Formed by monosaccharides joined my glycosidic bonds they are all insoluble)

Amylose (Starch)

Found in plants,major energy source, formed from a glucose, straight chains that are coiled (1 to 4), very compact (can be stored in small spaces), insoluble and does not affect osmosis.

Amylopectin (Starch)

Formed from a glucose, branched chains (1 to 6), Large surface area (enzymes can work faster, hydrolyses faster), also insoluble.

Glycogen

Found in animals and bacteria (similar to starch), formed from a glucose (1 to 4 and 1 to 6), also insoluble and compact, more highly branched than Amylopectin and can be rapidly broken down (important for respiration as animals move more than plants).

Cellulose

Formed from B glucose (1 to 4), straight chains that run parallel with hydrogen bonds (forms fibrils between chains that add strength), used in plant cell walls.