DNA replication - the main stages

Replication of DNA - deoxyribonucleic acid biosynthesis.The material for DNA biosynthesis is adenosine, guanozin- tsitidin- and timidintrifosfornaya acid or ATP, GTP, CTP and TTP.

mechanism of DNA replication

biosynthesis performed in the presence of so-called "seed" - a certain number of single-stranded deoxyribonucleic acid and transformed catalyst.The catalyst acts DNA polymerase.This enzyme participates in the compound of the nucleotide residues.In one minute, connects more than 1,000 nucleotide residues.The nucleotide residues in a molecule of deoxyribonucleic acid fragment interconnected 3 ', 5'-phosphodiester bonds.DNA polymerase catalyzes the addition of mononucleotides residues to the free 3-hydroxyl end Transformed deoxyribonucleic acid.First, a small portion of synthesized DNA molecules.They lend themselves to the action of DNA ligase to form a long fragments of deoxyribonucleic acid.Both fragments are localized in the nuclei of cells.Transformed deoxyribonucleic acid is used as a future point of growth of the DNA molecule and is also a matrix in which is formed an antiparallel circuit of deoxyribonucleic acid, which is identical in structure to the transformed DNA sequence and placement of nucleotide residues.DNA replication occurs during interphase of the mitotic cell division.Deoxyribonucleic acid is concentrated in the chromosomes and chromatin.After the formation of single- deoxyribonucleic acid formed its secondary and tertiary structures.Two strands of deoxyribonucleic acid are interconnected by hydrogen bonds by the rule of complementarity.DNA replication occurs in the nucleus of cells.

material for the biosynthesis of various groups and species of RNA is rich compounds: ATP, GTP, CTP and TTP.Ribonucleic acid can be synthesized therein with participation of one of the three fragments: the DNA-dependent RNA polymerase, polynucleotide nucleotidyltransferases and RNA-dependent RNA polymerase.The first of these is contained in the nucleus of all cells, mitochondria are also open.RNA was synthesized on a DNA template in the presence ribonukleozidtrifosfatov, Mangan and Magnesium ions.Formed RNA molecule complementary to DNA template.To DNA replication occurred in nuclei are formed p-RNA, t-RNA and RNA-RNA and priming.The first three are transported to the cytoplasm, where participating in protein biosynthesis.

DNA replication occurs almost as well as the translation of deoxyribonucleic acid.Transmission and conservation of genetic information is carried out in two steps: transcription and translation.What is a gene?Gene - a material unit, which is part of deoxyribonucleic acid molecules (RNA in some viruses).Contained in the chromosomes of the cell nucleus.The genetic information is transferred from DNA via RNA to protein.Transcription is carried out in the cell nucleus and is the synthesis of mRNA on sections of deoxyribonucleic acid molecule.It should be noted that the sequence of nucleotides of deoxyribonucleic acid "rewritten" in the nucleotide sequence of the molecule and RNA.RNA polymerase is joined to a corresponding portion of the DNA "unwinds" and its double helix structure of the copy deoxyribonucleic acid nucleotides adjoining the principle of complementarity.As you move the chain synthesized RNA fragments detached from the matrix, and the DNA double helix behind the enzyme immediately restored.If the RNA polymerase reaches the end and copied portion moves away from the RNA template in karyoplasm then moves into the cytoplasm, where it takes part in protein biosynthesis.

During the broadcast placement nucleotide sequence in the molecule and RNA translates into a sequence of amino acid residues in a protein molecule.This process takes place in the cytoplasm and RNA are combined and formed polysomes.