nucleic acids (nucleus - core) - organic compounds, which are associated with all the basic processes of existence of living matter.These biopolymers F. Miescher first isolated (1968) with the nuclei of leukocytes.Later nucleic acids have been identified in all cells of humans, animals and plants, microbes and viruses.Thus, it was proved that the compound of biological cells contained in all organisms are the main carriers of hereditary information, are involved in the biosynthesis of proteins of an organism.
nucleic acids presentation
Nucleic acids are prosthetic groups nucleoprotein.The end products of hydrolysis - purine and pyrimidine bases, pentose and phosphoric acid.By chemical composition distinguish deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).The DNA enters the monosaccharide composition - deoxyribose, composed of RNA - ribose.These compounds differ in the nitrogenous bases, the structure of molecules, cellular localization and functions.
compounds whose molecules consist of purine or pyrimidine bases and pentose (ribose, deoxyribose), called nuklozidami.Name nuleozida determined by nitrogen compounds, which is part of its structure.For example, a nucleoside which includes adenine called adenosine, guanine - guanosine, cytosine - cytidine, uracil - uridine, thymine - thymidine.Depending on the carbohydrate making up the molecules distinguish rubonukleozidy and deoxyribonucleosides.
addition to the basic nitrogenous bases, nucleic acids also contain so-called minor purine and pyrimidine base number (1 methyladenine, dihydrouracil, 1-methylguanine, 3 metiluratsil pseudouridine et al.).
nucleotides are nucleoside phosphoric esters.The molecule consists of a nucleotide purine or pyrimidine base, a pentose (ribose or deoxyribose) and phosphoric acid residue that binds to the fifth or the third atom Carbo pentoses.
nucleic acid structure and function.
individual nucleotides are joined together in this form di-, tri-, tetra-, penta-, hexa-, hepta- and polynucleotides, i.e. nucleic acids.Nucleic acids are composed of hundreds or thousands of individual nucleotides that are joined together by a hydroxyl group, located near the 3'-Carbo atom of the pentose of one nucleotide with residual phosphoric acid that is located near the 5 'th atom Carbo pentose next nucleotide.
DNA are the primary genetic material of all living biological systems.In organisms, except viruses and bacteria, it is localized in cell nuclei.A small amount of the acid is concentrated in the mitochondria and chloroplasts.
ribonucleic acids have been identified in almost every cell fraction.The largest amount of RNA is concentrated in ribonucleoprotein components - ribosomes.It should be noted that the bulk of the RNA contained in the cytoplasm, and only 10-15% of the part of the nucleus.
RNA based cell localization, biological function, molecular weight divided into three types: ribosomal, transport and matrix.
ribosomal RNA localized in the cytoplasmic granules of ribosomes, where they are firmly bound to the protein.They are characterized by a high molecular weight.Transport RNA are mainly hyaloplasm cell nuclear fluid in mitochondria and chloroplasts.They have a low molecular weight (40 thousand. Daltons).Their main function is the transport of activated amino acids from amino acid complex - AMP enzyme to the site of protein synthesis, that is, to the ribosomes.Scientific studies have proven that each amino acid has its own individual tRNAs.Today there are more than 60 kinds of transfer RNA.
messenger RNA (messenger RNA).Each molecule in the synthesis of the mRNA in the nucleus receives information from DNA and transfers it to the ribosomes where it is implemented in the biosynthesis of proteins.