B5

B5

1. Dna - Making Proteins

   • Dna molecules contain a genetic code containing instructions for how to make all the proteins in your body.
     • A-T , G-C
   • Dna is a double helix of Paired bases
   • Dna controls the production of proteins in a cell
     • Cells make proteins by joining amino acids together
   • Proteins are made by ribosomes in the cell cytoplasm

2. Cell Division

   • Mitosis
     • New cells are needed for growth and repair
     • First the cell grows and duplicates its contents
       • Then it splits into two by Mitosis
   • Meiosis
     • Forms sperm or egg cells called Gametes
       • Produces new cells that only have half the original number of chromosomes
     • Involves TWO divisions

3. Animal Development

   • Have lots of cells that are specialised to do a particular job
   • Cells in an early Embryo can turn into any type of cell
   • Cloning can be used to make stem cells
   • Stem cells may be able to cure many diseases

4. Phototropism and Auxins

   • Phototropism is growth towards or away from light
   • Auxins are plant Growth Hormones