Biological molecules

Carbohydrates
1. Monosaccharides
  1. Monomer
  2. 1 sugar molecule
  3. Glucose and fructose eg.
  4. Reducing
2. Disaccharides
  1. Dimer
    1. Formed by condensation reaction
  2. 2 sugar molecules
  3. Sucrose, lactose, maltose eg.
  4. Reducing and non reducing
3. Polysaccharides
  1. Polymer
  2. Many molecules
  3. Storage
    1. Starch (plant)
    2. Glycogen (animal)
  4. Structural
    1. Cellulose (cell wall)
    2. Chitin (exoskeleton)
Inorganic ions
1. Mg2+
  1. Component of chlorophyll
2. Fe2+
  1. Component of haemoglobin
3. PO42+
  1. Component of nucleotides (which form DNA, rNA) and phospholipids
4. Ca2+
  1. Hardens bones, teeth, cell wall
Water
1. High specific heat capacity
  1. Takes a lot of energy for temperature to change
2. High latent heat of vapourisation
  1. Lots of heat energy to make it evaporate
    1. Sweating and other evaporation cooling methods get rid of a lot of heat
3. Transparent
  1. Transmit light
    1. Plants under the surface can photosynthesise
4. Density
  1. Less dense than ice (highest density at 4 degrees celsius)
    1. Ice floats and insulates organisms that live underwater
5. Hydrogen bonds
  1. Bonds between surface molecules create surface tension
6. Polar
  1. Dissolves polar molecules like ions
    1. Main transmitter of substances and site of reaction in the body
7. Adhesion to hydrophilic surfaces
  1. Adheres to the walls of narrow tubes like xylem vessels
    1. Can travel up tubes against the pull of gravity
Lipids
1. Phospholipids
  1. Phosphate head
  2. Glycerol
  3. Fatty acid tails
2. Triglyceride
  1. Condensation
    1. Glycerol and 3 fatty acids
3. Fats
  1. Saturated
    1. Single bonds
    2. Soiid
    3. Raise cholesterol levels
      1. Clog arteries
        Heart disease and heart attacks
  2. Unsaturated
    1. Double bond(s)
    2. Liquid
4. Cholesterol
  1. LDL
    1. Bad cholesterol
    2. Builds up in arteries
    3. To lower LDL...
      1. Statins
      2. Exercise
      3. Diet
  2. HDL
    1. Good cholesterol
    2. Removes LDL from blood
    3. Statin and exercise increase levels
Protein structure
1. Primary
  1. Amino acid sequence
    1. Amino acids
      1. Amino group (NH2)
      2. Acid carboxyl group (COOH)
      3. +R group
      4. 20 amino acids in body
        10 synthesised in body
        10 essential amino acids (from diet)
      5. Condensation reaction
        Peptide bond
      6. Can be acidic, basic, neutral
2. Secondary
  1. Due to H bonding
  2. a-helix
    1. Coiled
    2. intra-strand
  3. b-sheet
    1. Pleated
    2. inter-strand
3. Tertiary
  1. 3D shape (protein folding)
    1. 4 different bonds
      1. Disulphide (double)
      2. Ionic
      3. Hydrogen
      4. Hydrophobic/hydrophilic
4. Quaternary
  1. Two or more polypeptides
  2. Prosthetic group
  3. eg. in haemoglobin or collagen
Food tests
1. Lipids
  1. Ethanol + cold water
    1. Emulsion
  2. eg. oils and fats
2. Starch
  1. Iodine solution
    1. Turns blue/black
  2. eg. amylose
3. Protein
  1. Biuret + invert
    1. Turns lilac
  2. eg. albumen
4. Sugar
  1. Reducing
    1. Benedict's reagent
      1. Turns opaque orange
    2. eg. glucose
  2. Non-reducing
    1. HCl, heat, sodium bicarbonate, Benedict's reagent, heat
      1. Turns orange
    2. eg. sucrose

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Biological molecules

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	Created by Halle Preston about 7 years ago