Chapter 19 section 1 The Chemistry of Life

Proteins A protein is an organic polymer composed of amino acids bonded together in one or more chains. ( C,H,N,O) ( A polymer is a large molecule formed from joining large number of small units known as monomers.

Polypeptide or protein How do monomers become polymers? Amino acid (monomer) Amino acid (monomer) Amino acid (monomer) Amino acid (monomer) Polypeptide or protein polymer

An amino acid has a central carbon atom, to which are bonded a carboxyl group, an amino group, a hydrogen atom, and a variable side chain designated as R, as shown in the following structural formula.

Structure of amino acid

Amino acids bond to each other by forming a peptide bond, an amide group formed by a condensation reaction between the carboxyl group of one amino acid and the amino group of another. This reaction is known as condensation or dehydration ( removing water)

Bonding between amino acids At one end of the protein carboxyl group and at the other end amino group) H R1 O H R2 O --- + H N C C O H + H N C C O H + --- H H H 2 O Water is removed The carbon atom from first amino acid will bond to nitrogen atom in the second one and so on……. H R1 O H R2 O N C C N C C Structure of protein H H Peptide ( amide)

Carbohydrates Familiar carbohydrates include sugars, starches, and cellulose. ( C,H,O)

(2 molecules of glucose). C12 H22O11 Sugar Monosaccharides are the simplest form of carboahydrate molecules, e.g. glucose, fructose and galactose.C6 H12O6 Disaccharides They are formed when two sugar molecules join together where water molecule is removed. ( dehydration reaction) Monosaccharide + monsaccharide disaccharide + water e.g. sucrose (glucose and fructose), lactose (glucose and galactose) and maltose (2 molecules of glucose). C12 H22O11

Polysaccharides Polysaccharides are made up of many monosaccharide's molecules joined together, e.g. starch, cellulose ,glycogen, and pectin

Lipids Lipids are fats and oils ( Triglycerides) They are made from Glycerol and fatty acids Glycerol is an organic compound contains three OH groups O CH2 OH HO C R + O CH OH HO C R +3H2O O CH2 OH HO C R Glycerol Fatty acid

Structure of monosaccharide