DNA

Long lengths of DNA can make up sections called genes. Lots of genes make up a chromosome. We have 23 pairs of chromosomes in each cell, making 46 - 23 from each parent.

• A gene is a section of DNA, contains instructions to make a protein
• Cells make proteins by stringing amino acids in an order
• 20 amino acids used, make thousands of proteins
• Genes tell cells in what order to put the amino acids together
• DNA determines what proteins the cell produces
• Determines what type of cell it is (red blood cell, skin cell, etc)

Everyone's DNA is unique, except for identical twins and clones.

DNA fingerprinting involves cutting up a strand of someone's DNA into small sections and then separating them on a piece of card. This is used in forensic science (eg to discover whose hair was left at the crime scene) and in paternity testing.