There are 20 amino acids, each differing in its R group. Two examples are: Glycine, its R group being H(Hydrogen) and Phenylalanine its R group being CH2 (Carbon Hydrogen). Amino Acids are joined together in proteins by peptide bonds. The three dimensional shapes gives a protein its function, if the protein shape is distorted the protein will not function properly. Even if the peptide bonds between amino acids remain intact the protein may still be dysfunctional. A protein with a distorted shape is denatured. There are several different types of protein: Fibrin, Collagen, Myogloblin and Keratin to name a few. Proteins are required for growth, repair and maintenance of muscles, blood internal organs, skin, hair, and nails, with endless functions. The word protein is a derivative from the Greek word protas meaning primary or "first".
I 'd like to expound on the protein Fibrin. Fibrin is an elastic insoluble whitish protein that aids in blood coagulation. Fibrin is made from fibrinogen. Fibrinogen is a protein made in the liver and is important in blood clotting. A clot forms due to an injury once blood is exposed to the air. The platelets, developed in the bone marrow and are parts of a large cell called megakarocytes, are very important in blood clotting. If broken apart at the introduction of air the platelets react with fibrinogen beginning the formation of fibrin. The platelets, protein fibrin and red blood cells block the damaged area, sealing the wound.
The transformation of Fibrinogen to fibrin is the final stage in blood clotting. Fibrinogen makes fibrin functional. Fibrinogen, along with
Cited: -www.hnf.org.uk/questions/index.asp -en.wikipedia.org/wiki/Fibrin -www.tiscali.co.uk/reference/encyclopedia/Hutchinson -book.google.com/books.comprehensive biotechnology XII pg5 -Life on Earth/Audesirk,Teresa;Audesirk,Gerald;Beyers,Bruce E.-4th edition;pg 31-33,384,386