AS Level biology.
In addition to the primary structure there is a specific secondary structure. The most common secondary structure is an extended spiral spring, the alpha helix, whose structure is maintained by many hydrogen bonds which are formed between neighbouring CO and NH groups. The H atom of the NH group of one amino acid is bonded to the O atom of the CO group four amino acids away.thus amino acid 1, would be bonded to amino acid 5, number two to number 6, and so on. X-ray diffraction data indicate that the alpha helix makes one complete turn for every 3.6amino acids.
The primary structure is the sequence of amino acids in a polypeptide chain. The first person to work out the complete amino acid sequence of a protein was Fred Sanger, working at the Cavendish laboratory in Cambridge, where Watson and crick also determined the structure of DNA. He worked with the hormone insulin, the smallest protein he could find.
Can you still remember the slogan "As valuable as a small steak"? He comes from an advertisement for fruit curd, should point to the high content of protein, which you supposedly can only find in a piece of meat. But is actually a steak-the ultimate source of protein? And for what, except for the muscle we need protein? Makes the fabric really slim?