biological molecules

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Created by: Emily BIrch
Created on: 03-05-13 08:48

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biological molecules
- water
  - solvent
  - transports nutrients
  - molecule made of one oxygen atom and 2 hydrogen atoms
  - slightly positive charge
  - dipolar molecule
  - hydrogen bonding
  - very cohesive
- carbohydrates
  - monosaccharides
    - joined by gl;ycosidic bonds
    - condensation reactions
    - alpha glucose
    - beta glucose
  - disaccharides
    - two monosaccharides joined together
    - lactose and sucrose
- lipids
  - triglycerides
    - glycerol and hydrocarbontail of fatty acids.
    - tails are hydrophobic
    - lipids insoluble in water
    - formed by condensation reactions
    - ester bonds
  - saturated or unsaturated
    - saturated lipids are mainly found in animal fats
    - unsaturated lipids are mostly found in plants
    - unsaturated lipids melt in lower temperatures than saturated ones.
    - hydrocarbons- unsaturated lipids - double bonds. saturated bnds- no double bonds.
- proteins
  - long chains of amino acids
  - dipeptide - two amino acids joined together
  - proteins made up of polypeptides
  - amino acids
    - carboxyl group
    - amino group NH2
    - difference between amino acids is the variety between R group
  - structure
    - primary - sequence of amino acids in the polypeptide chain
    - secondary - hydrogen bonds form between amino acids.alpha helix or beta pleated sheet.
    - tertiary - 3d structure . coiled folded structure.
    - quaternary - more than one polypeptide chain. 3d structure
  - globular
    - round, compact proteins made up multiple polypeptide chains.
    - coiled
    - soluble
    - e.g. haemoglobin
  - fibrous
    - insoluble
    - polypeptide chains
    - collagen
- enzymes
  - biological catalyst
    - metabolic reactions
    - intracelluar or extracellular
  - they lower the activation energy of a reaction.
  - globular proteins
  - active site with a specific shape
  - concentration affects the rate of reaction.
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