topic 1

• Polysaccharide


  Formed by the condensation of many glucose units held by glycosidic bonds
• Glycosidic bond


  C–O–C link between two sugar molecules formed by a condensation reaction, it is a covalent bond
• Monosaccharide

  The monomers from which larger carbohydrates are made
• Fibrils


  • Long, straight chains of β-glucose held together by many hydrogen bonds
• Condensation reaction


  A reaction that joins two molecules together with the formation of a chemical bond, involves the elimination of a molecule of water
• Non-competitive inhibitor


  • A molecule that binds to an enzyme at the allosteric site, causing the active site to change shape, preventing enzyme-substrate complexes from forming
• Phospholipid


  • Formed by the condensation of one molecule of glycerol and two molecules of fatty acid held by two ester bonds, a phosphate group is attached to the glycerol
• Induced-fit model

  The enzyme active site is not initially complementary to the substrate, the active site moulds around the substrate, this puts tension on bonds, lowers the activation energy
• Polymer


  Molecules made from a large number of monomers joined together
• Polysaccharides

  • Cellulose
  • Glycogen
  • Starch
• Polysaccharides

  • Amylose
  • Amylopectin
• Competitive inhibitor


  • A molecule that is the same/similar shape as the substrate, binds to the active site, prevents enzyme-substrate complexes from forming
• Hydrolysis reaction


  A reaction that breaks a chemical bond between two molecules, involves the use of a water molecule
• Disaccharide

  Formed by the condensation of two monosaccharides held together by a glycosidic bond
• Triglyceride

  • Formed by the condensation of one molecule of glycerol and three molecules of fatty acids forming 3 ester bonds
• Primary structure

  The sequence of amino acids on a polypeptide chain
• Secondary structure

  The folding or coiling to create a β pleated sheet or an α helix
• Activation energy

  The energy required to start a chemical reaction
• Quaternary structure


  More than one polypeptide chain in a protein
• Allosteric site


  A site on an enzyme where a molecule can bind and cause a change in the enzyme's shape
• Secondary structure

  The folding or coiling to create a β pleated sheet or an α helix held in place by hydrogen bonds
• Effect of substrate concentration on enzyme-controlled reaction

  • At low substrate concentrations, there will be fewer collisions between the enzyme and substrate
  • At high substrate concentrations, the rate plateaus because all the enzyme active sites are saturated
• Hydrophobic


  The tendency to repel and not mix with water
• Effect of temperature on enzyme-controlled reaction

  • At low temperatures, there is not enough kinetic energy for successful collisions between the enzyme and substrate
  • At too high a temperature, enzymes denature, the active site changes shape, and enzyme-substrate complexes cannot form
• Monosaccharides exist as two isomers: α glucose and β glucose
• Ester bond


  A chemical bond formed between glycerol and fatty acids
• Polypeptide


  A polymer chain of a protein made up of amino acids bonded together by peptide bonds following condensation reactions
• Carboxyl group


  The COOH group made up of a C with hydroxyl (OH) and carbonyl (double-bonded O) group bonded to it, found in amino acids and fatty acids
• Amine group


  The NH2 group found on amino acids
• Disulfide bonds


  Strong covalent bonds between two sulfur atoms in the R groups of different amino acids
• Hydrogen bonds


  Weak bonds that form between H and O in many biological molecules, e.g., proteins, water, DNA, tRNA
• Molecule that binds to an enzyme

  A molecule that binds to an enzyme
• Peptide bond


  Covalent bond joining amino acids together in proteins
• Sequence of amino acids on a polypeptide chain

  1. Secondary structure

  2. Tertiary structure

  3. Quaternary structure
• Effect of enzyme concentration on enzyme-controlled reaction

  • At low enzyme concentrations, there will be fewer collisions between the enzyme and substrate
  • At high enzyme concentrations, the rate plateaus because there are more enzymes than the substrate, leading to many empty active sites
• Tertiary structure

  The further folding to create a unique 3D shape held in place by hydrogen, ionic, and sometimes disulfide bonds
• Disaccharides

  • Lactose
  • Sucrose
• Effect of pH on enzyme-controlled reaction

  Too high or too low a pH will interfere with the charges in the amino acids in the active site, breaking the ionic and hydrogen bonds holding the tertiary structure in place, causing the active site to change shape and the enzyme to denature
• Monosaccharides

  • Glucose
  • Fructose
  • Maltose
  • Galactose
• Hydrophilic


  The ability to mix, interact, or attract water