Adenosine triphosphoric acid – ATP
Nucleotides serve as constituents for many important organic substances, for example, for substances that perform an energetic function in the cell: ATP, GTP, etc.
The universal source of energy in all cells is ATP – adenosine triphosphate, or adenosine triphosphate.
ATP is found in the cytoplasm, as well as in cell nuclei and in two-membrane organelles (plastids and mitochondria). This substance is the main source of energy for biochemical processes that take place in the cell.
ATP provides energy for all cell functions: mechanical work, biosynthesis of substances, division, etc. On average, the content of ATP in a cell is about 0.05% of its mass, but in those cells where ATP costs are high (for example, in liver cells, striated muscles), its content can reach 0.5%.
ATP is a nucleotide consisting of a nitrogenous base – adenine, a carbohydrate ribose and three phosphoric acid residues, two of which store a large amount of energy.
The bond between phosphoric acid residues is called macroergic (it is denoted by the ~ symbol), since when it is broken, almost 4 times more energy is released than when other chemical bonds are cleaved.
ATP is an unstable structure, and upon separation of one phosphoric acid residue, ATP is converted into adenosine diphosphate (ADP), releasing 40 kJ of energy.
Other derivatives of nucleotides
Hydrogen transporters constitute a special group of nucleotide derivatives. Molecular and atomic hydrogen is highly reactive and is released or absorbed during various biochemical processes. Nicotinamide dinucleotide phosphate (NADP) is one of the most widely used hydrogen transporters.
The NADP molecule is capable of attaching two atoms or one molecule of free hydrogen, transforming into the reduced form NADPH2. In this form, hydrogen can be used in various biochemical reactions.
Nucleotides can also take part in the regulation of oxidative processes in the cell.
Vitamins are complex organic compounds that are required by living organisms for the normal course of biochemical processes in small quantities. Vitamins differ from other organic compounds in that they are not a source of energy or initial substances for the formation of cellular organelles. Some vitamins are synthesized in the body itself, but most of these substances come from food. And bacterial cells can independently produce almost all the vitamins they need.
Vitamins are commonly referred to as the letters of the Latin alphabet. They are divided into two groups: water-soluble (B1, B2, B5, B6, B12, PP, C) and fat-soluble (A, D, E, K).
Vitamins take part in the metabolism mainly as an integral part of complex enzymes. Their absence or deficiency leads to severe disorders of the body’s vital functions.