Lipids mind map
- Created by: Rosiem2102
- Created on: 06-03-19 11:32
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- Lipids
- A group of substances containing a large amount of carbon and hydrogen that are soluble in alcohol instead of water because they are non-polar molecules
- Triglycerides
- Lipids made of one glycerol molecule and 3 fatty acids joined by ester bonds
- Energy source - can be respired to release ATP
- Energy store - insoluble in water and high proportion of hydrogen means that 1g of fat releases twice the amount of energy as 1g of glucose
- Insulation - the adipose tissues of animals store lipids for insulation
- Buoyancy - fat is less dense than water and so can help animals float
- Protection - can form a layer of mechanical insulation around delicate organs
- Phospholipids
- A glycerol molecule bonded to two fatty acids and one phosphate group
- They are found in cell membranes in the phospholipid bilayer
- The phosphate group is the head of the molecule and is hydrophilic so dissolves on the outside of the bilayer
- The fatty acid tails are hydrophobic so form a barrier that water-soluble molecules cannot pass across
- Cholestorol
- A polar molecule consisting of hydrocarbon rings attached to a hydrocarbon tail
- A relatively small molecule with a fat shape
- Can fit into the phospholipid bilayer to strengthen it, making it less fluid
- Glycolipids - carbohydrate attached to a lipid with a glycosidic bond
- Fatty acids
- Saturated: there are no C=C double bonds and the molecule has as many hydrogen atoms as is possible
- Unsaturated: there is at least one C=C double bond (1 bond would be mono unsaturated, more C=C bonds would make a polyunsaturated fat) and, as a result, the molecule contains fewer hydrogen atoms
- C=C double bonds are kinked and so an unsaturated fatty acid takes up more space than a saturated fatty acid. This means that unsaturated fats have lower melting points
- Ester bonds
- Each glycerol molecule can form covalent ester bonds with up to three fatty acids
- The reaction to form ester bonds is a condensation reaction - water is another product of the reaction and water is used when the bond is hydrolysed
- The water molecule released is made from the OH group of the fatty acids and the hydrogen from an OH group from the glycerol
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