The Gene's Code for Life
While the English language has 26 letters, each gene's orders, or instructions, are written in a chemical code of four. The code is made up of chemical bases called adenine, thymine, guanine and cytosine. We call these A, T, G and C - the gene code's four letters. Long lines, or sequences, of these chemicals permit each of the 70,000 or so genes to have a different code that directs the making of a different protein. One gene = one code = one protein. The proteins carry out the gene's instructions.
Proteins -- not just beans and a big, juicy steak, but a key to all life!
There are thousands of proteins, each made up, in part, of nitrogen, the colorless gas that makes up most of our air. Proteins are found in animal muscle (steak) and skin, bone and all the "stuff" of life, every cell of an animal or plant. They are also what make the body work: They are necessary for the chemical reactions that make muscles flex, brains think, and stomachs produce digestive fluids.
Think of genes as the orders or plans for a house. (This house could be your body, your dog 's body or your petunia plant.) Picture the proteins as not only the nuts and bolts, plaster and concrete, wood beams and floors, but also as the workers that create and assemble these things and set the furnace and lights and gas stove to working.