Bio Difficult

• What is a limiting factor?

  the factor that will slow the rate of increase when in short supply
• Amino acid structure

  • COOH = carboxylic acid group
  • R = variable side group
  • NH2 = amine group
• Haemoglobin

  • Globular conjugated protein with prosthetic group
  • 2 α-chains, 2 β-chains
  • 4 Fe2+ prosthetic haem groups
  • Water-soluble so dissolves in plasma
  • Tertiary structure changes so it is easier for next O2 molecules to bind (cooperative binding)
• Paper/ thin-layer chromatography

  Use capillary tube to spot solution onto pencil 'start line' (origin) 1 cm above bottom of paper

  2. Place chromatography paper in solvent. (origin should be above solvent level)

  3. Allow solvent to run until it almost touches other end of the paper. Molecules in mixture move different distances based on relative solubility in solvent/attraction to paper.
• Rf values


  Rf value = spot movement / solvent front movement