In a cage there are thousands of types of proteins, each of them has the specific function. Squirrels participate in creation of organelles of a cage, its membranes and covers and also blood vessels, tendons and hair.
Proteins in living cell
In living cell not less than a half of dry weight of a cage falls to the share of proteins. Proteins are present at all cages without exception, and they can be found in any part of a cage. All proteins in an organism, regardless of their functions and biological activity, are constructed of the same set of twenty standard amino acids. Proteins differ from each other in the fact that the sequence of amino-acid links is characteristic of each of them.
Construction function of proteins at plants and animals
Proteins — an obligatory component of all cellular structures. Plants and some of bacteria can synthesize amino acids of which their proteins consist. For this purpose they use inorganic compounds: carbon dioxide, nitrogen, hydrogen and substances of the soil. Animals lost ability to synthesize ten complex irreplaceable amino acids, it occurred in the course of evolution. Therefore they receive them with vegetable and animal food in finished form.
Proteins are split to amino acids in a digestive tract, then they are soaked up in blood and get to cages where own proteins characteristic of this organism are under construction of ready amino acids. Amino acids contain in meat, eggs, fish, dairy products, beans and some plants. Protein — the main construction material for fabrics, in the course of biosynthesis it provides growth and development of an organism.
Examples
Some proteins give mechanical durability to fabrics of a living organism. Collagen concerns to such proteins, it is the main proteinaceous component of an extracellular matrix of connecting fabric. At mammals it makes about a quarter of lump of all proteins, collagen in fibroblasta — cells of connecting fabric is synthesized. At first procollagen is formed, the predecessor of protein, after a certain chemical treatment in fibroblasta it turns into three polypeptide chains twisted in a spiral which unite in collagenic fibrilla. Fibrilla forms the collagenic threads seen under a microscope. At all vertebrata protein a keratin is synthesized, it is the main structural component of hair, horns, nails, wool, scales and feathers. Elastic fabrics, for example, in walls of blood vessels and skin contain protein the elastin capable to stretch, and then to revert to the original state.