HideShow resource information
View mindmap
  • Lipids
    • Characteristics
      • Contain carbon, hydrogen, oxygen
      • Insoluble in water
      • Soluble in organic solvents e.g. alcohols/acetone
    • Roles
      • Source of energy- broken down in respiration
      • Buoyancy- used by aquatic mammals to help stay afloat
      • Insulation
      • Protection- humans have fat around vital organs
      • Energy store- insoluble in water, can be stored without affecting water potential of cell
    • Triglycerides
      • Three fatty acids combined with glycerol
      • Each fatty acid forms ester bond with glycerol in condensation reaction
      • Large, non-polar, insoluble: their storage does not affect water potential
      • Release water when oxidised
      • Low mass to energy ratio, lots stored in small space.
    • Phospholipids
      • Hydrophillic head, hydrophobic tail.
      • Polar, form a bilayer within cell surface membrane (barrier) selectively permeable, stability
      • Heads help hold them at surface of membrane
      • Structure allows them to form glycolipids by combining with carbohydrates. Glycolipids aid cell recognition.
    • Test for lipids
      • Take a dry, grease free test tube.
      • Add 5cm3 ethanol to 2cm3 sample.
      • Shake to dissolve lipid
      • Add 5cm3 water, shake gently
      • Cloudy white colour indicates presence of lipid
      • CONTROL: Repeat using water instead of sample- solution should remain clear
    • Cholestrol
      • Four carbon based rings
      • Small, hydrophobic
      • Made in liver of animals


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Biological molecules resources »