Biological molecules

Carbohydrates
Lipids
1. Can exist as fats, oils and waxes
2. Made up of C,H and O
3. Vast majority are Triglycerides
  1. roles of triglycerides
    1. Energy reserves
    2. electrical insulation eg. myelin in nerve cells
    3. Thermal insulation eg.blubber
    4. Metabolic source of water eg. in camels
    5. waterproofing eg. the waxy cuticle in plant leaves
  2. structure of triglycerides
    1. Three fatty acid molecules combine with one glycerol molecule
      1. fatty acids have a Carboxyl group(COOH)
  3. Triglycerides are bad conductors and have no charge
  4. Cholesterol-is also a lipid but is not a triglyceride
    1. Made up of 4 carbon rings
    2. Found in cell membranes
      1. It's hydrophobic nature allows it to sit between the Phospholipid tails within the cell membrane
        So it can work to regulate fluidity and strength of the membrane
Water
1. structure
  1. One oxygen atom covalently bonded to two hydrogen atoms
  2. oxygen atoms have slight negative charge and hydrogen atoms have slight positive charge, therefore water is a polar molecule
    1. other polar molecules( e.g. salts,glucose, amino acids) will disolve in water, but non-polar molecules are insoluble in water.
2. Roles
  1. Plays an important role in the blood, lymphatic,excretory and digestive systems, as it is very good at transportation due to being a solvent
3. properties
  1. Thermal properties
    1. High specific heat capacity-means aquatic species are more able to adapt to a stable environment
      1. This means lots of heat is needed to make water evaporate from the body, so sweating is very effective at cooling us down
  2. Density and freezing properties
    1. solid from less dense than liquid form (so large bodies of water don't often freeze )
    2. High density is also used for support and protection e.g. Amniotic fluid in the womb
  3. cohesion and surface tension
    1. Cohesion occurs because hydrogen bonds pull water molecules in at the surface
      1. Cohesion is responsible for surface tension-allowing small organisms to walk on water
Proteins
1. Structure
  1. long chains of amino acids
    1. central Carbon atom attached to four groups
      1. Amino group-NH
        Amnio groups are basic-alkaline in water
      2. Hydrogen atom-H
      3. R group-varies between amino acids
      4. Carboxyl group- COOH
        Carboxyl groups are acidic
        Anything with alkaline and acidic regions is amphoteric, meaning it can resist tendency to change its PH, therefore amino acids are amphoteric
    2. There are 20 amino acids, all of which plants produce, however animals only produce 12 and so they need to consume the other 8
  2. Two bonded amino acids=dipeptides Multiple bonded amnio acids=polypeptiedes.
  3. amino acids are held together by polypeptide bonds
Nucleic Acids
Enzymes

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Biological molecules

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	Created by megan hill over 7 years ago