Proteins Essay example -- science

ProteinsProteins be the macromolecules of life. Discovered in 1838, proteins argon recognized as a large number of superior organic compounds that make up aliment organisms and atomic number 18 essential to their functioning. The term protein comes from the Greek word proteies or master(a). Proteins yield m either diverse properties and function in a course of ways. They lowlife function as a building material, in teeth, swot and muscles, and they can serve as enzymes, hormones, and neurotransmitters. Its functions are the most diverse of any family. Whether put up in humans, animals, plants or in single-celled bacteria, proteins are do of units of 20 different amino group demigods. Proteins consist of macromolecules called polypeptides, make from monomers called amino acids. Proteins have hundreds, thousands, or sometimes even millions of these amino acids. These amino acids are made up of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. few proteins consist of only single polypeptides. In most cases it involves two or more combined polypeptides, sometimes with other small organic molecules or metal ions. The most basic aim of protein structure, called the primary structure, is the linear rank of amino acids. Different successivenesss of the acids along a chain, however, affect the structure of a protein molecule in different ways. Proteins secondary structure often contains long stretched out chains of amino acids called strands that line up together to make sheets. These are called beta strands and the sheets are called beta-pleated sheets. A protein may contain either or both of import helices and beta pleated sheets. Alpha helices and beta pleated sheets are joined by less(prenominal) clear structures often grouped together under the name of coil. Some small proteins may be made of coil. Shape is also important. Proteins are coiled and twisted, giving it a unique plaster cast. The shape depends on the season of the amino acids, which can be deliquescent or hydrophobic. Those that are hydrophilic want contact with water and will be twisted to maximize contact. Those that are hydrophobic are twisted in such a way to minimize contact. Changing one amino acid in the polypeptide season can destroy this shape and make the protein function improperly if not at all. A very important function that proteins can serve are to act as catalysts. Enzymes are organic catalysts ma... ... cells their shape and as well as parts of the linkages that stick cells together into tissues and organs. So, the sequence of amino acids in all proteins is genetically determined by the sequence of nucleotides in cellular DNA. So basically Proteins are basic constituents in all living organisms. They are complex molecules composed of amino acid and necessary for the chemical processes that occur in living organisms. Proteins are sometimes referred to as macromolecular polypeptides because they are very large molecules and because the amino acids of which they are composed are joined by peptide bonds. The vast majority of the proteins found in living organisms are composed of only 20 different kinds of amino acids, repeated many times and strung together in a particular order. Each type of protein has its own unique sequence of amino acids. Also each protein makes every living organism different. Bibliography 1. Proteins, Lexicon ordinary Encyclopedia, 1989 Volume 15, pg.576. 2. www.biotech.imcb.edu.com 3. http//www.faseb.org/protein.html 4. Proteins. SceinceDaily.2000 www.sceincedaily.com 5. Proteins. Britannica Online 2000 www.britanncia.com