Doubling with the formation of two identical copies is a completely normal phenomenon in biological systems. Often this doubling is called replication. The latter can occur at different levels of matter organization - from directly DNA to chromosomes and whole cells. Moreover, if the process went smoothly, two identical units are obtained. Replication is jewelery exact doubling.
Like nowhere exactly
The most interesting and basic for all other species is DNA replication. This is a process that takes place over several stages, at each of which accuracy is critical, because inaccuracy will provoke the synthesis of an absolutely wrong protein, unsuitable for use in the cell and in the body as a whole.
The beginning of time
Cell replication begins with a duplication of DNA, which results in a duplication of chromosomes. But replication is the cornerstone of the whole process. It consists of three stages: firstly, initiation, secondly, elongation, and thirdly, termination. The work of enzymes begins with special points - replicators and only with them. Starting in the wrong place would distort the whole process. The enzyme catalyst activates specific proteins that form the prereplication complex necessary for DNA doubling. Before propagation, DNA is cut into two parts by special enzymes.
Complementary chain
During elongation, a complementary maternal chain is built on the matrix. That is, one that can then form an integral molecule. The process ends with termination, which also occurs at a certain point. There is a special unit - a replicon. This is the DNA fragment that is being built at a time. DNA replication is the basis; without it, chromosome replication is impossible. The latter occurs when the cell prepares for division.
Protein as a sign
Duplication of the chromosome begins just a few hours after DNA doubling has occurred. To rebuild the chromosome, not only new sets of deoxyribonucleic acid are needed , but also the proteins that make up the chromosome apparatus, and their synthesis takes time. Accelerated replication is a sign of cancer. If too much protein is found that is characteristic of intense cell division, the doctor will begin to sound the alarm.
Enough space
There is an interesting peculiarity in the process of replication - in the space of the nucleus the points of synthesis of new DNA are located fairly evenly, thus, there are no distortions that could provoke mutual influence. There are quite a lot of points, as a rule, one and a half to two dozen.
How exactly chromosomes are organized depends on whether mitosis or meiosis occurs in the cell. In the first case, the formed cell will have the usual set, in the second - half. After all, the remaining half will bring the cell of the second partner in sexual reproduction. If in meiosis suddenly a complete set is obtained, the reproductive cell will either be non-viable, or a sick child will be conceived. However, such babies are still most often not born, there is a miscarriage at an early stage of pregnancy, which the mother can take for menstruation or ovulation bleeding in the middle of the cycle.