B3 Part I

Molecules of Life
1. Mitochondria
  1. Tiny structures found in the cells. Respiration occurs here
  2. Respiration-Releases energy from glucose
  3. Tissues/organs have large numbers of it e.g. liver and muscle cells
2. Ribosomes
  1. Can be seen with electron microscope
  2. Found in the cytoplasm and are in the site of protein synthesis
3. Chromosomes
  1. Cells nucleus contains chromosomes
  2. Long coiled molecules of DNA
4. DNA
  1. The information contained in genes is in the form of instructions called genetic coding
    1. Genetic coding controls cell activity, meaning it controls some characteristics of the organism
  2. Controls the production of different proteins
    1. Needed for growth and repair of cells
  3. Structure
    1. Two chains wound into a double helix
    2. Each strand is made of chemical bases
      1. G-C-A-T
        Base pairs G-C and A-T
    3. Two strands coil together to form a double helix
      1. With chemical cross links between the two strands , formed by pairs of bases
  4. Genes and proteins
    1. contains a different sequence of bases and codes for a particular protein
    2. Proteins are made in the cytoplasm
    3. Genes cannot leave nucleus
      1. Copy is made which is able to leave the nucleus
    4. Making proteins
      1. G-C-A-T
      2. Protein structure is determined on Base Codes
      3. Each amino acid coded by sequence order of three bases
      4. mRNA(messenger RNA)
        Copied DNA is carried by mRNA
        mRNA from DNA = Transcription
        Proteins from mRNA is called translation
  5. Controls the function of a cell by controlling its production of proteins
    1. e.g. enzymes
Proteins and mutations
1. Proteins
  1. Polymers
    1. Large molecules made from many smaller molecules
  2. Each protein molecule built from amino acids
    1. which are smaller monomer molecules
      1. Join end to end making protein polymer molecule
  3. Each protein has own number of sequence of amino acids
    1. Gives the protein a particular shape allowing a particular function to be carried out
  4. Types of protein
    1. Structural = Collagen
    2. Hormone = Insulin
    3. Carrier molecule = Heamoglobin
    4. Enzyme = Amylase
2. Enzymes
  1. Biological catalysts
    1. speed up chemical reactions
  2. Catalyse chemical reactions in living cells
    1. Respiration
    2. Photosynthesis
    3. Protein synthesis
  3. Active Sites
    1. Shape determines how it works
    2. active sites are where the substrate molecules fit into when the reaction happens
      1. Substrate molecule - a substance on which the enzymes react
    3. Has to be right shape for the substrate molecules to fit into
      1. enzymes have high specificity for their substrate
        A particular enzyme with particular substrates
  4. Temperature
    1. At low temp enzyme reactions are slow
    2. Reaction speeds up as temp rise until an optimum temp is reached
    3. After this point the slow down and eventually stop
    4. Steady increase between 0-40'C ussally optimum is around 40
  5. pH
    1. optimum pH like temp
3. Mutations
  1. Spomtaneous
  2. Happen because of
    1. Radiation
    2. Chemicals such as tar from cigarette smoke
  3. Harmful or Helpful
    1. Often harmful
  4. Genes can be switched on and off
    1. mutations can alter the production of certain protiens
4. Changing shape of the active site will cause reaction to slow
  1. Eventually the reaction will stop
    1. Enzymes become denatured
5. Q10 = measure of the rate of change of a reaction when the temperature us uncreased by 10'C
  1. Many of Q10 of 2
  2. Q10 = rate at higher temperature / rate at lower temperature

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B3 Part I

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	Created by Gurwinder Singh over 10 years ago