MENU
 |
日本語版 |
| Japanese |
DNA directionality
In the reproduction of DNA, the directionality of the DNA chain has an important meaning.
The direction of the of DNA strand is determined by the orientation of the phosphate bond, one strand is oriented "5 '→ 3'" of the double-stranded DNA and the other is oriented "3 '→ 5'" it.
As for the process of replication, first the Double-stranded DNA is wound back, and the binding of the base is removed.
This is similar to the case of the messenger RNA, a gap is formed between the double-stranded DNA.
Subsequently the DNA chain enzymes are oriented "3 '→ 5'", the synthesis of DNA is performed.
Then, the Enzyme moves in the direction of "3 '→ 5'" over a DNA single strand to the combine complementary nucleotide bases of DNA, furthermore It unites a nucleotidic fellow and creates a complementary DNA chain.
Double-stranded DNA is wound back and, when you come to a place where a Y-shaped bifurcated end portion of the coupling is disconnected, enzyme changes direction.
It is said this point is "the replication fork"
Then it is time to move in the opposite direction and the DNA was oriented "5 '→ 3'" so, the complementary DNA strand is synthesized to this chain.
However, at this time, DNA synthesis is not continuous.
It forms a small RNA chain of DNA that is oriented "5 '→ 3'" and it will continue to synthesize DNA and to fill the blanks.
Finally, cut out a portion of the RNA, bind the DNA synthesis and of its parts, and we have a complete DNA strand.
In replication of DNA, such process proceeds in the replication origin the presence of DNA from place to place, two double-stranded DNA are made.
The speed of DNA replication is approximately 7 hours in the case of a person making DNA strands with the length of 1.8m.
Design by