proteins, carbohydates and lipids

• protein is made up of amino acids
• amino acid has an R group which can be different
• amino acids are the building blocks of protein
• a polypeptide chain is formed by linking together many amino acids with peptide bonds
• a polypeptide chain is formed when amino acids join together by peptide bonds
• lipid is made up of fatty acid chains
• carbohydrate is made up of monosaccharides
• fatty acid chains have hydrocarbon tails that are non-polar
• polysaccharides have lots of sugar units joined together
• disaccharides have two sugar units joined together
• monosaccharides are simple sugars
• how dipeptide formed?


  dipeptide are formed by joining two amino acids in condensation reaction
• how is polypeptide formed?

  polpeptides are formed by condensation of many amino acids joined by peptide bonds
• give three examples of different amino acids

  1. Glycine
  2. Alanine
  3. Leucine
• name the three types of carbohydrates?

  1. monosccharides
  2. disaccharides
  3. polysaccharides
• define fibrous protein


  are made up of polypetide chains. structural role, long insoluble. are often structural proteins that provide strength and protection to cells and tissue.
• name fibrous protein and their functions

  • collagen- adds stregnth to tissues
  • kertatin- helps form the tissue of the hair and nails and outer layer of the skin - epidermis. it helps support your skin , heal wounds and keep your nails and hair healthy.
  • myosin
• amino sequence of fibrous sequence

  repetitive with limited range of R groups
• globular protein


  metabolic role, functional.

  amino acid sequence: is irregular and wide range of R groups

  structure: spherical and are soluble in water
• examples of globular

  • haemoglobin- transports oxygen from the lungsto the tissue and facilating the return of carbon dioxide
  • amylase
  • insulina
  • elastin
• monosaccharide

  • contain one sugar molecule and include: glucose, fructose andand glactose
  • soluble- dissolve in water to give sweet solution
• disaccharides

  • made up by joining two or more monosaccharides molecules together in a condensation reaction reaction. this is called glycosidic bond.
  • are soluble in water
  • examples are: maltose, sucrose, lactose
• disaccharides examples 


  glucose + glucose = maltose

  glucose + fructose = sucrose

  glucose + galactose = lactose
• polysaccharides

  • are polymers of monosaccharide monomers.
  • made up of many monosaccharides, joined together by condensation resction and held by glycosidic bonds
  • insoluble, not sweet
• examples of polysaccharides

  1. starch
  2. glycogen
  3. cellulose
• starch

  • is a mixture of two polysaccharides ,amylase and amylopectin
  • Amylase- is an unbranched chain of glucose molecules held by 1, 4 glycosidic bonds. amylase is coiled and compact therefore stores lot of energy.
  • amylopectin- branched chain made up of glucose molecules joined by 1,4 and 1,6 glycosidic bonds . it has side branches where energy is released.
• key properties of starch

  • it is insoluble so it will not affect water potential
  • compact, so lots of energy can be stored
• glycogen

  • is formed from many molecules of alpha gluclose joined together by 1,4 and 1,6 glysosidic bonds
  • it has large amount of side branches, which means that energy can be realsed quickly
• cellulose

  • is composed od long, unbranched chains of beta glucose which are joined by glycosidic bonds
  • microfibrilis are strong threads which are made of long cellulose chains running parallel to one another that is joined together by hydrogen bonds forming cross linkages.
• protein structure

  1. primary structure
  2. secondary structure
  3. tertiary structure
• primary structure


  the sequence with which amino acids appear in the chain
• secondary structure


  either an alpha or beta pleated sheet, held in place by hydrogen bonds
• tertiary structure


  the precise folding of the polypeptide chain held in place by hydrogen bonds and disulphide bonds
• quaternary structure


  two or more polypeptides bonded together by hydrogen bonds and disuphide bonds
• protein functions

  1. hormone production
  2. transportation
  3. enzyme production
  4. source of energy
  5. buid and maintain tissue
• define lipids

  are biological molecules made carbon, hyrdogen, oxygen.
• properties of lipids

  • long, nonpolar hydrocarbon tails
  • insoluble
  • the molecule is hydrophobic, which means water hating
• structure of lipid


  lipids consists of two or three fatty acids, which are joined to a molecule of glycerol in condensation. the fatty acids have long, hydrocarbon chains
• main two types of lipids

  1. triglycerides
  2. phospholipds
• triglycerides


  a triglycerides are lipids made up of glycerol and three fatty acids joined by ester bonds formed in condensation.

  for example- fats and oils. these are used mostly as energy stores as well as insulation ( under the skin) and protection