B3 - B

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  • Created by: zoolouise
  • Created on: 02-06-15 17:55
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  • Proteins and mutations
    • Grouping organisms
      • All proteins are made of long chains of amino acids
      • Proteins have different functions.
        • Structural proteins are used to build cells and tissues e.g collagen
        • Enzymes
        • Hormones which carry messages to control a reaction e.g insulin
        • Carrier proteins e.g haemoglobin
      • Each protein has its own number and order of amino acid.
        • This gives each type of protein molecule a different shape and function.
    • Enzymes
      • Enzymes speed up reactions in the body and are therefore called biological catalysts.
      • They catalyses chemical reactions occurring in respiration, photosynthesis and protein synthesis in living cells.
      • The subtract molecule fits into the enzyme active site like a key fitting into a lock, hence the'lock and key mechanism'
        • This explains why each enzyme can only work on a certain substrate. It's called specificity and happens as the substrate has to be the right shape.
      • Enzymes all work best at a certain pH and temperature, this is called the optimum and any change away from it slows down the reaction.
        • At low temperatures molecules are moving more slowly and the enzyme and substrate are less likely to collid.
          • At very high or low pH's or very high temperatures the enzyme active site starts to denature and therefore the substrate cannot fit and it can't react as quickly.
      • Calculating the Q10 works out how temperature alters rate of reaction.
    • Mutations
      • Mutations may occur spontaneously but can be made to occur by chemicals and radiation
      • When they occur they can give an individual an advantage, be harmful but with no effect, produce a different protein
      • Every cell has the same genes but doesnt mean the same proteins are made. Different genes are switched off in diff cells, allows diff cells to perform diff functions.
      • Mutations alter or prevent production of protein thats normally made, they change the base code of DNA and therefore the order of amino acids im proteins.


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