Karen A. Beitler
Collagen is a polymer of proteins. A protein is a natural polymer made up of amino acid monomers joined by peptide bonds. Amino acids are chains of glucose molecules that have a carboxyl (COOH) and an amine group (NH
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) on either end. Peptide bonds, or amide linkages, are covalent bonds formed between the carboxyl and amine groups. Proteins are also known as polypeptides. A dipeptide is made up of two amino acids, a tripeptide of three amino acids; tetrapeptide of four amino acids, more than four amino acids is referred to as a polypeptide. Polypeptides can be found in four levels of structure; primary, secondary, tertiary and quaternary. Each one is more complex.
Primary structure proteins are a chain of amino acids connected by peptide bonds, like a string of beads. Secondary structures have hydrogen bonds that twist like a telephone cord and form alpha helices or beta sheets. Tertiary structures are formed when folding and bending of amino acid chains causes interaction and bonding between groups. This is when proteins become active. Quaternary structures contain two or more amino acid chains and are even more folded and bent forming fibrous, globular or conjugated (reversibly combined) structures
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. Collagen has a quaternary structure and is a fibrous or structural (insoluble) protein. Cellulose, a carbohydrate, provides the material for the basic structure of plants and collagen (protein) provides the material for the basic of animals. There are at least sixteen forms of collagen known and their basic structure is a triple helix
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. These molecules are made of carbon, hydrogen, oxygen and nitrogen with a few other elements, their long chains and myriad of combinations formulate a multitude of parts that constitute all life forms on Earth.
The formation of protein polymers provides the foundation for the construction of living things. Actin is the most abundant protein in eukaryotic cells. Actin allows movement inside and outside the cell. Actin is said to be highly conserved across species, which means that very little difference can be found between actin in the cells in humans or in the cells of algae
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. Proteins are not lone molecules, of course, carbohydrates, as discussed earlier and lipids play critical roles in the makeup of living things as well. Yes, this is all chemistry! Life is made of molecules the same way plastics are made of long chains of molecules. And most man-made polymers are based on formulas taken from nature.