Replication

DNA replication is a process for producing copies of two identical DNA molecules of the original. Occurs in all living organisms, this biological process is the basis for inheritance of biological. The DNA, is comprised of two components, each strand of the DNA molecule of the original, serves as a template for the preparation process, the complementary strand of replication and semi-preservation. Error and mobile edit checks to ensure a mechanism of perfect fidelity near for DNA replication. In the cell, in the genome, DNA replication begins at the origin of replication or location specific. Deployment of the synthesis of new strands result in replication fork to increase the origin and two-way base in DNA. Many proteins, promote replication fork, is associated with the continuation and initiation of DNA synthesis. Most importantly, the synthesis of new DNA by DNA polymerase is the addition of nucleotides complementary to the template strand.

Illustration of DNA Replication

DNA replication can be carried out by (extracellular artificially) in vitro. DNA polymerases isolated from synthetic DNA primers and cells, can be used to initiate DNA synthesis of sequences known to one molecule of the DNA template. To amplify the target DNA fragment of a specific polymerase chain reaction (PCR), from the group of the periodic DNA, Experimental common technique applied by the artificial synthesis.

Cell division is essential for an organism to grow, but when cells divide, daughter cells of both to have the genetic information the same as their parents, there is a need to respond to the DNA in the genome it. It provides a simple mechanism for DNA replication in the double-stranded structure of DNA. Here, separating the two strands and then the complementary strands of the DNA sequence is reconstructed by an enzyme called DNA polymerases each. By finding the correct base through a connection with the base pair added to the original direction, this enzyme produces a complementary strand. In order to be able to extend the DNA strand in the 5 ‘to 3’ direction, a different mechanism is used to copy the antiparallel strand of the double helix DNA polymerase. [97] Thus, it is determined based might appear in a new direction based on the old circuit, the cell ends with a complete copy of their DNA.

DNA polymerases are a family of enzymes that carry out all forms of DNA replication. , But also does not allow you to start the synthesis of new chains in general, DNA polymerase, can be linked to the circuit pattern, to extend the RNA strand DNA or existing. To start the fusion, is connected to the stranded DNA template and is created, a short piece of RNA is called a primer.

The synthesized strands of new DNA by extending the 3 ‘end of the nucleotide sequence of the existing addition of new nucleotides, DNA polymerase, matching one by one through the formation of phosphodiester bonds in the template strand. Energy for this process comes to DNA polymerization by hydrolysis high energy phosphate (phosphoanhydride) connected between the phosphate 3 associated with each unincorporated base. (In particular, the free base having a phosphoric acid group attached is called a nucleoside triphosphates. Called nucleotides connected database phosphate group 3) during DNA strand nucleotide grows and the nucleotide phosphate nearest chain that if growth were added to the formation of phosphodiester bonds is responsible for hydrolysis of high energy phosphate bond in the release of remote phosphate of two, such as pyrophosphate. The enzymatic hydrolysis of inorganic phosphoric acid pyrophosphate obtained, consumes high energy phosphate bonds of the second, the reaction becomes irreversible effectively.

In general, within the error rate of error of less than 107 nucleotides of the addition of all, it is very accurate the DNA polymerase. In addition, DNA polymerases some are correction capability Further, they may be employed to correct the mismatched bases, to remove nucleotides from the end of the growing chain. Finally, it is possible that the replication mechanism of mismatch repair after DNA for monitoring errors and distinguish conflicts DNA strand newly synthesized from the sequence of the original circuit. In summary, you can enable the replication fidelity of one error of less than 109 nucleotides of all form of discrimination, these 3 steps are added.

Rate of DNA replication in living cells is measured as a percentage of elongation of phage T4 DNA in E. coli infected with phage first. DNA is through increased exponentially in 30 ℃, speed is 749 nucleotides per second. Is from 8.10 to 1.7 by the mutation rate of the base pairs of the replication of T4 phage DNA synthesis between. Thus, DNA replication is accurate impression quickly.

Usually, DNA exists as a double-stranded structure with two strand wound together to form a double helix properties. Chain each single DNA strand of four types of nucleotides. Nucleotides of DNA, contains a nucleic acid base sugar, deoxyribose, and phosphate,. Four types of nucleotides corresponding to the omission often four nucleotides adenine base, cytosine, guanine, thymine, as and is a purine base as thymine and cytosine so that it is a pyrimidine guanine C, and T. Adenine and G. These nucleotides deoxyribose of the DNA double helix having a nucleobase pointing inside of forming phosphodiester bonds – Create a phosphate backbone. Match between the strands through hydrogen bonds to form a base pair of nucleotides (bases). Pairs of adenine and thymine and Guaninpea (two hydrogen bonds) and (three hydrogen bonds) cytosine.

And “(3 prime) end 3 ‘” “5” have a direction, a different part of the thread is called (5 prime) end in the DNA strand. ‘When 3, the right end portion of the terminal sequence’ by end convention chains. Double helix is ​​5, 5 ‘to 3’ left edge of the array if the given nucleotide sequence of one strand of “DNA , it is anti-parallel to one of the ‘to 5’ direction opposite strand 3. these terms, attach, please refer to the carbon atoms of the deoxyribose phosphate-next in the chain. DNA polymerase DNA strand By adding nucleotides to the 3 ‘end of focus so as not be able to synthesize the DNA in a single direction, the pairing of bases in DNA by. hydrogen bonds has the consequence of DNA synthesis , it is possible, which means that the information contained in each field is redundant. use in the reconstruction of the nucleotide chain partner nucleotides of one strand is synthesized de novo.