Organic and inorganic substances. Inorganic substances of the cell
Chemical substances were first classified at the end of the 9th century by the Arab scientist Abu Bakr al-Razi. Based on the origin of the substances, he divided them into three groups. In the first group he assigned a place to mineral substances, in the second to plant substances and in the third to animal substances.
This classification was destined to last for almost a millennium. Only in the 19th century two of those groups were formed - organic and inorganic substances. Chemical substances of both types are built thanks to the ninety elements included in D.I. Mendeleev’s table.
Group of inorganic substances
Among inorganic compounds, simple and complex substances are distinguished. The group of simple substances includes metals, nonmetals and noble gases. Complex substances are represented by oxides, hydroxides, acids and salts. All inorganic substances can be built from any chemical elements.
Group of organic substances
The composition of all organic compounds necessarily includes carbon and hydrogen (this is their fundamental difference from mineral substances). Substances formed by C and H are called hydrocarbons - the simplest organic compounds. Hydrocarbon derivatives contain nitrogen and oxygen. They, in turn, are classified into oxygen- and nitrogen-containing compounds.
The group of oxygen-containing substances is represented by alcohols and ethers, aldehydes and ketones, carboxylic acids, fats, waxes and carbohydrates. Nitrogen-containing compounds include amines, amino acids, nitro compounds and proteins. For heterocyclic substances, the position is twofold - they, depending on their structure, can belong to both types of hydrocarbons.
Cell chemicals
The existence of cells is possible if they contain organic and inorganic substances. They die when they lack water and mineral salts. Cells die if they are severely depleted of nucleic acids, fats, carbohydrates and proteins.
They are capable of normal life if they contain several thousand compounds of organic and inorganic nature, capable of entering into many different chemical reactions. The biochemical processes occurring in the cell are the basis of its vital activity, normal development and functioning.
Chemical elements that saturate the cell
Cells of living systems contain groups of chemical elements. They are enriched with macro-, micro- and ultra-microelements.
- Macroelements are primarily represented by carbon, hydrogen, oxygen and nitrogen. These inorganic substances of the cell form almost all of its organic compounds. They also include vital elements. A cell is not able to live and develop without calcium, phosphorus, sulfur, potassium, chlorine, sodium, magnesium and iron.
- The group of microelements is formed by zinc, chromium, cobalt and copper.
- Ultramicroelements are another group representing the most important inorganic substances of the cell. The group is formed by gold and silver, which have a bactericidal effect, and mercury, which prevents the reabsorption of water that fills the kidney tubules and affects enzymes. It also includes platinum and cesium. Selenium plays a certain role in it, the deficiency of which leads to various types of cancer.
Water in the cell
The importance of water, a common substance on earth for cell life, is undeniable. Many organic and inorganic substances dissolve in it. Water is a fertile environment where an incredible number of chemical reactions take place. It is capable of dissolving decay and metabolic products. Thanks to it, waste and toxins leave the cell.
This liquid has high thermal conductivity. This allows heat to spread evenly throughout the body tissues. It has a significant heat capacity (the ability to absorb heat when its own temperature changes minimally). This ability prevents sudden temperature changes from occurring in the cell.
Water has exceptionally high surface tension. Thanks to it, dissolved inorganic substances, like organic ones, easily move through tissues. Many small organisms, using the property of surface tension, stay on the water surface and slide freely along it.
Turgor of plant cells depends on water. In certain species of animals, it is water that copes with the support function, and not any other inorganic substances. Biology has identified and studied animals with hydrostatic skeletons. These include representatives of echinoderms, round and annelids, jellyfish and sea anemones.
Saturation of cells with water
Working cells are filled with water by 80% of their total volume. The liquid exists in them in free and bound form. Protein molecules bind tightly to bound water. They, surrounded by a water shell, are isolated from each other.
Water molecules are polar. They form hydrogen bonds. Thanks to hydrogen bridges, water has high thermal conductivity. Bound water allows cells to withstand cold temperatures. Free water accounts for 95%. It promotes the dissolution of substances involved in cellular metabolism.
Highly active cells in brain tissue contain up to 85% water. Muscle cells are 70% saturated with water. Less active cells that form adipose tissue need 40% water. It not only dissolves inorganic chemicals in living cells, it is a key participant in the hydrolysis of organic compounds. Under its influence, organic substances, breaking down, turn into intermediate and final substances.
The importance of mineral salts for the cell
Mineral salts are represented in cells by cations of potassium, sodium, calcium, magnesium and anions HPO 4 2-, H 2 PO 4 -, Cl -, HCO 3 -. The correct proportions of anions and cations create the acidity necessary for cell life. Many cells maintain a slightly alkaline environment, which remains virtually unchanged and ensures their stable functioning.
The concentration of cations and anions in cells is different from their ratio in the intercellular space. The reason for this is active regulation aimed at transporting chemical compounds. This course of processes determines the constancy of chemical compositions in living cells. After cell death, the concentration of chemical compounds in the intercellular space and cytoplasm reaches equilibrium.
Inorganic substances in the chemical organization of the cell
The chemical composition of living cells does not contain any special elements that are unique to them. This determines the unity of the chemical compositions of living and nonliving objects. Inorganic substances in the composition of the cell play a huge role.
Sulfur and nitrogen help proteins form. Phosphorus is involved in the synthesis of DNA and RNA. Magnesium is an important component of enzymes and chlorophyll molecules. Copper is necessary for oxidative enzymes. Iron is the center of the hemoglobin molecule, zinc is part of the hormones produced by the pancreas.
Importance of inorganic compounds for cells
Nitrogen compounds convert proteins, amino acids, DNA, RNA and ATP. In plant cells, ammonium ions and nitrates are converted into NH 2 during redox reactions and become involved in the synthesis of amino acids. Living organisms use amino acids to form their own proteins needed to build their bodies. After the death of organisms, proteins flow into the cycle of substances; during their decay, nitrogen is released in free form.
Inorganic substances that contain potassium play the role of a “pump”. Thanks to the “potassium pump,” substances that they urgently need penetrate into the cells through the membrane. Potassium compounds lead to the activation of cell activity, thanks to which excitations and impulses are carried out. The concentration of potassium ions in cells is very high, in contrast to the environment. After the death of living organisms, potassium ions easily pass into the natural environment.
Substances containing phosphorus contribute to the formation of membrane structures and tissues. In their presence, enzymes and nucleic acids are formed. Various layers of soil are saturated to varying degrees with phosphorus salts. Root secretions of plants, dissolving phosphates, absorb them. Following the death of organisms, the remaining phosphates undergo mineralization, turning into salts.
Inorganic substances containing calcium contribute to the formation of intercellular substance and crystals in plant cells. Calcium from them penetrates into the blood, regulating the process of blood clotting. Thanks to it, bones, shells, calcareous skeletons, and coral polyps are formed in living organisms. Cells contain calcium ions and crystals of its salts.
