lipids

• what are lipids?


  commonly knows as fats and oils.they are a diverse group of hydrophobic (water hating) biological molecules.
• are lipids soluble or not?

  they are insoluble in water but soluble in inorganic (non polar) solvents such as acetone.
• what are lipids made from?

  made from a variety of different components but all contain hydrocarbons.the components theyre made from relates to the lipids function
• what are the 2 types of lipids?

  triglycerides and fatty acids.
• what are the 5 things lipids can be used for?

  1. plasma membrane- contributes to

  flexibility of membrane and transfer of

  lipid soluble substances across them

  2) waterproofing- waxy cuticles in plants

  and insects. mammals secrete oily

  substance

  3) energy source- concentrated

  4) insulation- helps retain heat under skin

  5) protection
• what do triglycerides contain?

  1 molecule of glycerol with 3 fatty acids attached to it. the fatty acids have long tails made of hydrocarbons which repel water as they are hydrophobic.
• how are triglycerides formed?

  they are formed via a condensation reaction between the fatty acid and glycerol molecule. this reaction forms an ester bond which releases a water molecule. this happens twice more to form a triglyceride.
• What are the 4 properties of triglycerides?

  1. large ratio of energy storing. carbon-hydrogen bonds - can be very readily hydrolysed to meet energy demands.

  2) high ratio of hydrogen to oxygen atoms - act as a metabolic water source

  3) large and hydrophilic making them insoluble- no effect on water potential so doesn’t cause osmosis

  4) relatively low mass- can be stored without increasing mass and preventing movement.
• What are the 2 types of fatty acids?

  Unsaturated- contains atleast 1 double bond between carbonsSaturated- contains only single bondsThe R groups of fatty acids which can vary in length and can be saturated or unsaturated.
• What are phospholipids?


  Nearly the same as triglycerides except one of the fatty acids are replaced by a phosphate group which is hydrophilic which contrasts the fatty acids which are hydrophobic.
• What do phospholipids make up in a cell?

  They make up the bilayer of cell membranes which control what goes in and out of a cell.
• What characteristics does the head and tails of a phospholipid have?

  The heads are hydrophilic and their tails are hydrophobic. This forms a double layer with their heads facing out to the water on each side. The centre is hydrophobic so water soluble substances can’t easily pass through.