In this video you will learn that proteins are natural polymers made up of amino acids and we find out why they have to be an essential part of our diet For healthy living proteins need to make up about 10% of the food we eat Plant seeds such as cereals, nuts, pulses (beans) are good sources of protein As are most animal products such as insects, fish, meat, eggs, and milk Proteins have two major functions in living things They are the enzymes that control all of the reactions that take place in the cells of all living things And they form the structural material in animals, hair, bone, skin, muscles and the vital organs Proteins are natural polymers made up of 20 different amino acids Look at the central carbon atom. It has four different groups attached to it The amino group, the acid group, the hydrogen atom, and the side chain, R. There are 20 different groups of atoms for R. For example, hydrogen, methyl, alcohol, etc. Organic compounds with two or more functional groups have the potential to polymerize Think of them like trucks of a train. The couplings are like the functional group. With only one group, you can only make a double molecule. But with two or more functional groups, you can make a long chain. This coupling works chemically by a condensation reaction where water is eliminated between the amino and acid groups making a peptide link. We begin the formation of polypeptides and eventually proteins. When we digest proteins it breaks back into the separate amino acids, so we can reassemble them into our own proteins. Enzymes have a primary structure. which is simply the polypeptide chain we have just seen. The secondary structure enables the protein to coil up like a twisted rope. Now the different side chains attached to each amino acid represented by the different colored Rs Stick out like bits of rag caught in the rope. Some of these will attract each other and some will repel enabling the rope, our protein, to coil up in a very specific 3-D shape giving it its Tertiary structure. Here’s how it works The genetic code of living things safely stored as DNA on the chromosomes in the nucleus of cells sends out a coded message telling the cell to construct a protein made of amino acids joined together in a unique order this coils up into its final 3D shape ready to catalyze one type of reaction needed by the cell. Finally a bit about the structural proteins that build the body of animals such as worms, insects, birds, fish and ourselves. Our biggest organ is our skin made of tough protein. Bones are made of a flexible tough protein, called collagen. Try feeling your ears. Then calcium phosphate a hard brittle insoluble salt is laid down making the bone a bit like reinforced concrete with the tough flexible collagen fibers like steel an the hard brittle cement around. Protein molecules in muscles are spread out and they contract when activated Spiders and some insects make threads out of proteins. They are very strong and tough but soft. So to summarize, we learned that Proteins are vital to all living things since they are the enzymes that control all the chemical reactions in their cells In addition, animals use proteins to build their vital organs Digestion breaks the protein we eat into amino acids which we can reassemble into the proteins we need.