Mineral substances in the cell are in the form of salts in a solid state, or are dissociated into ions.
Inorganic ions are represented by cations and anions of mineral salts.
cations: K +, Na +, Ca2 +, Mg2 +, NH + 4.
Anions: Cl–, H2PO – 4, HPO2–4, HCO – 3, NO – 3, SO2–4, PO3–4, CO2–3.
Together with soluble organic compounds, inorganic ions provide stable indicators of osmotic pressure.
The concentration of cations and anions in the cell and in its environment is different. Inside the cell, K + cations and large negative organic ions predominate; in the pericellular fluids, there are always more Na + and Cl– ions. As a result, a potential difference is formed between the contents of the cell and its environment, providing such important processes as irritability and the transmission of excitation along a nerve or muscle.
As components of the body’s buffer systems, ions determine their properties – the ability to maintain pH at a constant level (close to neutral reaction), despite the fact that acidic and alkaline products are continuously formed in the process of metabolism.
Example: anions of phosphoric acid (HPO2-4 and H2PO-4) create a phosphate buffer system in mammals that maintains the pH of the intracellular fluid in the range of 6.9-7.4.
Carbonic acid and its anions (H2CO3 and CO2-3) create a bicarbonate buffer system and maintain the pH of the extracellular medium (blood plasma) at 7.4.
Compounds of nitrogen, phosphorus, metals are needed for the formation of organic substances (amino acids, proteins, nucleic acids, ATP, etc.).
Example: ions of some metals (Mg, Ca, Fe, Zn, Cu, Mn, Mo, Br, Co) are components of many enzymes, hormones and vitamins or activate them.
Potassium – ensures the functioning of cell membranes, maintains acid-base balance, affects the activity and concentration of magnesium.
Ions Na + and K + contribute to the conduction of nerve impulses and excitability of the cell. These ions are also part of the sodium-potassium pump (active transport) and create the transmembrane potential of cells (provide selective permeability of the cell membrane, which is achieved due to the difference in the concentration of Na + and K + ions: there is more K + inside the cell, more Na + outside).
Calcium ions (Ca2 +) play a key role in the regulation of muscle contraction. Myofibrils have the ability to interact with ATP and contract only when certain concentrations of calcium ions are present in the medium. Calcium ions are also essential for the blood clotting process.
Iron is part of the blood hemoglobin.
Nitrogen is part of proteins. All the most important parts of cells (cytoplasm, nucleus, membrane, etc.) are built of protein molecules.
Phosphorus is part of nucleic acids; ensures normal growth of bone and dental tissue.
The lack of minerals leads to disruption of metabolic processes and negatively affects the life of the cell.