lipids

• lipids are any type of fat or oil. they are made of carbon hydrogen and oxygen
• there are two main groups of lipids: triglyceride and a phospholipid
• the difference between a phospholipid and a triglyceride is in a phospholipid one fatty acid is replaced with a phosphate head
• triglycerides are made in a condensation reaction between glycerole and fatty acids. this forms an ester bond
• in a triglyceride there is no pattern in hydrogen to oxygen ratio because there is a higher no. hydrogen
• fatty acid chains are r groups they can be saturated or unsaturated.
• the difference between unsaturated and sturated is double bonds between carbon
• properties of triglycerides are : high energy, good storage molecules, large and non-polar (insoluble in water so they dont affect osmosis in cells) and soluble in organic solvents (alcohol and acetone)
• in phospholipids the fatty acid tails are hydrophobic and the phosphate head hydrophyllic, this makes it a polar molecule. it makes up all cell memranes by controlling substances (phospholipid bilayer)
• in phospholipids the more unsaturated the fatty acids the more fluid the cell membrane
• carbohydrates combine with phospholipids to make glycolipids which are important for cell recognition
• lipids are sources of energy, they are insoluble in water, they provide insulationto retain body heat, fatty sheaths insulate nerve cells, protect delicate organs
• the emulsification test for lipids is:

  add ethanol to sample

  pour solution into water

  shake

  positive = whiite/milky emulsion