Cell Division

Cell divisions are controlled by transmitters. There is a group of genes that code for proteins which influence the cell cycle: stimulate or retard growth and divisions. They are called oncogenes. If they do not function properly they can cause cancer development. Transmitters are conveyed in blood. They adjoin the cell receptors and begin series of reactions proceeding in the direction to the nucleus that cause cell division. Disturbing the process reflect in the tumorous transformation of the cell.


transmitter adjoininig the cell receptor

The period of cell growth and synthesis of necessary substances is called interphase. It is divided into phases depending on if it is before, during or after the duplication of genetic material. RNA and protein synthesis occurs continuously throughout the interphase.

  • phase G1 (first gap)– activation of enzymes necessary to DNA synthesis (lasts between 6 and 12 hours for animal cells)

  • phase S (synthesis)– DNA replication, chromatin is duplicated in the cell nucleus from the beginning amount of 2n to 4n ( 6 to 8 hours depending on the dimensions of the genome)

  •  phase G2 (second gap)– (3-4 hours)

 

 

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