A gene codes for a specific protein:
- A gene is a section of DNA. It contains the instructions to make a specfic protein.
- Cells make proteins by stringing amino acids together in a particular order.
- Only 20 different amino acids are used to make up thousands of different proteins.
- The order of the bases in a gene simply tells in what order to put the amino acids together:
- Each set of three bases (called a triplet) codes for a particular amino acid.
- TAT codes for tyrosine and GNA for alanine.
- DNA also determines which genes will be turned on and off - and so which proteins the cell produces, e.g. haemoglobin or keratin. That in turn determines what type of cell it is, e.g. red blood cell or skin cell.
- Some of the proteins help to make all the other things that aren't made of protein (like cell membranes) from substances that come from your diet…