Bio Rev 2

Monosaccharide = simple sugar (CH2O)N, so if N= 3, = C3H6O3 3 = triose, 5 = pentose, 6 = hexose disaccharide = two monosaccharides join together When this happens its a condensation reaction so water removed [Gluc + Gluc = maltose] This is enzymed and reversible Disaccharide formula = [C6H10O5]n Other Disaccharides: -Sucrose [a-gluc + fruc], -Galactose [lac + fruc] All mono saccharids and some disaccharides are reducing sugars. Reducton is gain of electrons, so reducing sugars donate electrons to other subtances. Benedict's Test: Add 2cm^3 of Benedict's solution + food sample to test tube. Heat gently boiling tube for 5 minutes. Solution will appear GREEN ORANGE OR RED depending on how much reduc. sugar is present. [Due to Cu2+ being reduced to Cu+ which forms Cu+O = red] 18% of biomass in humans is composed of proteins Keratin in hair/nails Collagen in connective tissue They're involved in body functions: •enzymez •hormones •antibodies •haemoglobin Contain C,H,O + N All proteins are polymers of amino acid 20 diff. amino acids. Single protein can contain 1000s of monomers in any order so no of diff proteins is very big. Each diff amino acid has a diff R group. Amino acids join by condensation like carbohydrates to form a DI-PEPTIDE. Water is formed as always. Peptide bond formed. Polypeptide = chain of amino acids joined by peptide bonds. 1ary structure - sequence of amino acids 2ndary structure - 3D folding of the primary structure. Most common forms are Helises + B-Plated sheets 3iary structure - 3D folding of secondary structure. ALL regulatory proteins [eg enzymes] have complex tertiary structures. Different R-Groups may attract or repel each other and so primary structure determines 3iary structure. 3iary structure held by H-bond between R groups, ionic and covalent bonds, electric repulsion and DISULPHIDE Bridges.

4nary structure - This describes the arrangement of two or more polypeptides in proteins consisting of more than one. Fibrous = little or no tertiary structure + consist of long parralel polypeptide chains twisted into Ahelises. There may be H- bonds between these chains, and this makes these proteins very tough and insoluble. They are used mainly for STRUCTURAL purposes. EG Keratin in hair, Collagen in connective tissue. Globular = complex 3ary + 4nary structure + are folded into SPHERICAL shapes therefore GLOBULAR. Like enzymes + antibodies. TEST FOR PROTEINS - Biuret test that detects peptide bonds - Place sample of soution to be tested in a test tube and add an equal volume of NaOH [sodium hydroxide]. Add few drops of Copper [II] Sulphate and mix gently. Purple = PROTEIN!