It has been established that eighty-six elements from the periodic system are constantly present in the human body. To support life, twenty-five components are needed, of which eighteen are absolutely necessary, and seven are useful.
Such chemical elements of the cell as nitrogen and hydrogen, carbon and oxygen, occupy about 98% of its total mass. The content of other components is very small. So, for example, sulfur is present in an amount of 0.15-0.2%, and iodine accounts for only 0.000001%.
Cell chemicals include molecules of fats, nucleic acids, carbohydrates, proteins, carbon dioxide, oxygen and water. What is characteristic, in inanimate nature, all these components can not be found together anywhere.
Nucleic acids, which are part of the chemical composition of the cell, are the basis of ribonucleic and deoxyribonucleic acids. DNA and RNA are the custodians of genetic (hereditary) data.
Proteins ensure the existence of cells and, in addition, contribute to the fulfillment of their functions. Proteins account for half the dry weight of the cell.
These high molecular weight compounds are composed of amino acids. Due to the physical and chemical bonds between amino acids, proteins are compactly located inside the cell.
The primary structure of the protein looks like a thread. Subsequently (as synthesized), a secondary (similar to a spiral) is formed, and then a tertiary structure similar to a fibril (cord) or globule (ball). When several molecules are combined with each other or when they interact with non-protein molecules, a quaternary formation occurs. So, for example, a hemoglobin molecule is formed. It consists of globin (protein) and heme, a component of non-protein origin containing iron.
According to their biological purpose, proteins are divided into three categories. Enzymes belong to the first group. They are biological catalysts for chemical reactions. The second group includes mediators, hormones and other "specific" proteins. The third group contains structural molecules. They are necessary for updating and restoring the elements that make up the chemical composition of the cell.
Membranes are composed of phospholipids (fat molecules). Fats help maintain heat by being a heat insulator. Equally important is their importance in obtaining water. It is established that when burning a kilogram of fat, a kilogram and one hundred grams of water are obtained. In addition, these fatty components that make up the chemical composition of the cell are an indispensable energy source.
Carbohydrates also produce energy, mainly glucose and its polymer - glycogen. However, it is worth noting that the energy value of fats is six times greater than that of glycogen. At the same time, its reserves in muscles and liver are thirty times less.
Water is also part of the chemical composition of the cell. It is established that even in tooth enamel (the hardest tissue in the body) contains ten percent of water. In most cells, H2O accounts for between seventy and eighty percent; in bone cells, twenty percent.
Water, as you know, is a universal solvent. With the participation of 2, heat regulation is carried out. Also, all biochemical cellular reactions occur in it. Water determines many physical properties. So, for example, elasticity, volume and other characteristics are established. In addition, water takes an active part in the elimination of toxic products, the transport of nutrients, oxygen and other things, promotes metabolism.
In the process of energy transformations, oxygen enters the cells. It is a powerful natural oxidizing agent. One of the end products of cellular respiration is carbon dioxide.