molecular biology

• Vitalism


  Living organisms were composed of organic chemicals that could only be produced in living organisms because a vital force was needed
• synthesis of urea

  urea could only be made in living organisms because it is an organic compound
• Atoms


  Single particles of an element
• Molecules

  Groups of atoms held together by covalent bonds
• hydrogen bond forms between the positive pole of 1 water molecule and the negative pole of another - energy released when made and used when broken
• Methane has a melting point of -182°C and water has a melting point of 0°C
• The boiling point of water is 100°C at 760 mmHg pressure
• Hydrophilic


  Attracted to water, polar molecules that dissolve in water
• Hydrophobic


  Attracted to each other rather than to the non-polar molecules of water, insoluble in water
• Hydrogen nuclei are less attractive to electrons than oxygen nuclei
• Hydrogen has a positive charge and oxygen has a negative charge
• Water shows dipolarity
• Metabolism


  Web of all the enzyme-catalysed reactions
• Anabolism


  Synthesis, condensation reactions
• Catabolism


  Breakdown, hydrolysis reactions
• Properties of water


  • Cohesive
  • Thermal
  • Adhesive
  • Solvent
• 2 monomers = dimer
• Polymer


  Lots of monomers
• Carbohydrates


  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides


  1. Can be put together to form a disaccharide by condensation

  2. Disaccharide can then be made into a polysaccharide
• Monosaccharides


  Sugars that consist of a single monomer
• Condensation reactions


  1. 2 molecules are joined to form a larger molecule and a molecule of water
• Hydrolysis reactions


  1. Reverse of condensation

  2. A large molecule is broken down into smaller ones

  3. Water is used up
• Monosaccharides


  • Ribose
  • Glucose
• Triglycerides


  3 fatty acids and 1 glycerol- condensation
• Fatty acids


  • Saturated (single bonds)
  • Unsaturated (double bonds)
• Phospholipids


  2 fatty acids + 1 glycerol + phosphate group
• Cis


  Hydrogen atoms bonded to carbon atoms on the same side
• Trans


  Hydrogen atoms bonded to carbon atoms on opposite sides
• Steroids


  4 fused rings
• Lipids + carbs


  Used to store energy
• Lipids are 6x more efficient than carbs in the amount of energy that can be stored
• Body Mass Index (BMI)


  mass in kg / (height in m)²
• Trans fats are artificially produced and increase the risk of coronary heart disease
• Peptide bond formation


  1. Amino acids are linked by condensation reaction

  2. Consisting of 2 amino acids is a dipeptide

  3. Polypeptides consist of many amino acids
• Proteome


  All of the proteins produced by a cell
• The amino acid sequence of a polypeptide is coded for by a gene
• Protein


  Consists of either a single polypeptide or more than one linked
• Denaturation


  1. Heat/vibrations break intramolecular bonds

  2. Causes conformation to change

  3. Optimum pH is changed
• Protein conformation


  • Polypeptide folded into a globular shape
  • Sequence of amino acids determines the folding