DNA replication is the deoxyribonucleic acid biosynthesis process. The material for DNA biosynthesis is adenosine, guanosine, cytidine, and thymidine triphosphoric acid or ATP, GTP, CTF, and TTF.
DNA replication mechanism
Biosynthesis is carried out in the presence of the so-called "seed" - a certain amount of single-stranded transformed deoxyribonucleic acid and catalyst. The catalyst is DNA polymerase. This enzyme is involved in combining nucleotide residues. More than 1000 nucleotide residues are connected in one minute. The nucleotide residues in the molecule of the deoxyribonucleic acid fragment are interconnected by 3 ′, 5′-phosphodiester bonds. DNA polymerase catalyzes the attachment of mononucleotide residues to the free 3-hydroxyl end of the transformed deoxyribonucleic acid. First, small parts of the DNA molecule are synthesized. They lend themselves to the action of DNA ligase and form longer fragments of deoxyribonucleic acid. Both fragments are localized in the nuclei of cells. The converted deoxyribonucleic acid is used as the growth point of the future DNA molecule and is also the matrix on which the antiparallel chain of deoxyribonucleic acid is formed, which is identical to the transformed DNA in the structure and sequence of nucleotide residues. DNA replication occurs during the interphase of mitotic cell division. Deoxyribonucleic acid is concentrated in the chromosomes and chromatin. After the formation of a single-stranded deoxyribonucleic acid, its secondary and tertiary structures are formed. Two strands of deoxyribonucleic acid are interconnected by hydrogen bonds according to the rule of complementarity. DNA replication occurs in the nuclei of cells.
The material for the biosynthesis of different groups and types of RNA is macroergic compounds: ATP, GTF, CTF and TTF. Ribonucleic acid can be synthesized in them with the participation of one of the three indicated fragments: DNA-dependent RNA polymerase, polynucleotide nucleotidyl transferase and RNA-dependent RNA polymerase. The first of these is found in the nuclei of all cells, also discovered in the mitochondria. RNA is synthesized on a DNA template in the presence of ribonucleoside triphosphates, Mangan ions and Magnesium. An RNA molecule complementary to the DNA matrix is formed. In order for DNA replication to occur in the nuclei, r-RNA-, t-RNA-, and-RNA- and RNA-seeds are formed. The first three are transported to the cytoplasm, where they participate in protein biosynthesis.
DNA replication occurs in much the same way as the translation of deoxyribonucleic acid. The transmission, as well as the preservation of hereditary information, is carried out in two stages: transcription and translation. What is a gene? A gene is a material unit that is part of a deoxyribonucleic acid molecule (RNA in some viruses). Contained in the chromosomes of cell nuclei. Genetic information is transmitted from DNA through RNA to protein. Transcription is carried out in the cell nucleus and consists in the synthesis of i-RNA in parts of the deoxyribonucleic acid molecule. It should be said that the nucleotide sequence of deoxyribonucleic acid is “transcribed” into the nucleotide sequence of the i-RNA molecule. RNA polymerase binds to the corresponding DNA site, “uncoils” its double helix and copies the structure of deoxyribonucleic acid, adding nucleotides according to the principle of complementarity. As the fragment moves, the synthesized RNA strand moves away from the matrix, and the DNA double helix behind the enzyme is immediately restored. If RNA polymerase reaches the end of the copied region, RNA moves away from the matrix into the karyoplasm, and then moves to the cytoplasm, where it takes part in protein biosynthesis.
During translation, the sequence of nucleotide placement in the i-RNA molecule is translated into the sequence of amino acid residues in the protein molecule. This process occurs in the cytoplasm, i-RNA combines here, and a polysome is formed.