Biochemistry

Cadmium is a rather rare element on Earth 1.3 10' 5 % of the mass of the Earth ’ s crust). In humans, cadmium accumulates mainly in the liver, kidneys, and blood (in red blood cells). The physiological effect of cadmium in animals is due to its effect on the activity of certain enzymes and hormones and depends, first of all, on SH binding in proteins and other compounds. Cadmium compounds are highly toxic to humans. Fatal poisoning is caused by 50-60 mg of cadmium when taken orally. Cadmium oxide CdO and cadmium sulfate Cd(SO)4 arc particularly toxic. Entering the body in the form of vapors, smoke or dust, they affect the respiratory system, liver and kidneys. Cadmium poisoning is accompanied by a violation of phosphorus-calcium and protein metabolism (decalcification of the body occurs). At the same time, bone strength is reduced and urinary proteins are excreted through the kidneys. Typical symptoms of cadmium poisoning are severe headaches, dizziness, nausea, vomiting, salivation, and upper respiratory tract damage. Strontium. In the Earth's crust it contains 3.4-10' 2 %. Plants and animals are able to concentrate strontium. Strontium can enter the body of animals and humans through the respiratory tract, with food and water, as well as through damaged areas of the skin. Strontium does not form strong bonds with bioorganic molecules (proteins, etc.), therefore it does not stay in the blood and soft tissues for a long time, but concentrates in the mineral part of the bone tissue. Sr accumulates more intensely in the bones. Strontium in the body has the ability to displace calcium from its compounds. Replacing Ca 2 ' with Sr 2 ’ in the composition of the bone tissue causes brittle bones (strontium rickets). Particularly dangerous is the radioactive isotope of strontium-90 ( 90 Sr), whose half-life is 28.4 years. It appears during the explosion of nuclear charges or due to the leakage of radioactive waste into the environment. 90 Sr forms Sr(HCO 3 ) 2 bicarbonate, which is highly soluble in water, which migrates to water, soil, plants, and animal organisms. Accumulating in bones, 2(1 Sr irradiates the bone marrow and disrupts bloodformation processes. 1.2 ROLE OF WATER IN THE ORGANISM The content and distribution of water in the body. Along with proteins, carbohydrates, lipids, enzymes, vitamins and hormones in the cells of various organs, tissues and intercellular spaces contain inorganic substances, which include water and salts. Water is the most important component of all cells. In quantitative terms, it contains much more than other components. However, water is not only an integral part of cells, it also serves as a medium in which cells exist and through which 20