The nucleolus also disappears in the prophase. The chromosomes become visible in the nucleus and can be seen with a light microscope as tall and thin thread-like structures. At the beginning of prophase, the chromatin rearranges itself into tightly packed chromosomes and the gene transcription stops. During interphase, the nuclear material in cells is in the form of loosely packed chromatin to promote gene transcription. It is more likely a preparatory phase to begin the division of chromosomes. The four phases or steps of mitosis are as follows Although the process of mitosis is continuous, it is usually studied by dividing it into four phases for convenience. This process takes place in a series of four steps. Cell enters the mitotic phase with replicated DNA and is ready to undergo division of nucleus into two daughter nuclei. Mitosis occurs as a part of the mitotic phase of the cell cycle. Others stay in the G 0 phase throughout their life. Some cells during their lifetime receive signals for division and come out of the G 0 phase and enter the phase. If the cell does not receive signals for cell division, it enter the G 0 phase, a senescence phase in which no division occurs. The decision of whether the cell will undergo cell division or not takes place at the end of the G 1 phase. The phase between two cell divisions are collectively called interphase. The division of nuclear material is followed by cytokinesis, the division of cytoplasm, and the parent cell gives rise to two daughter cells. It is a phase of the cell cycle during which nuclear division takes place. The cell receives signals to undergo cell division and enters the M phase. The duplicated DNA is checked for errors, and proteins necessary for cell division are made at an exponential rate. G 2 Phaseĭuring the G 2 phase, the cell prepares itself for cell division. the nuclear material in the cell is doubled. As a result, chromosomes in cells consist of two identical chromatids i.e. S Phaseĭuring S phase, also called the synthetic phase, the cell undergoes DNA replication. These signals lead the cell to enter the next phase of the cell cycle, the S phase. At some time during this interphase, the cell receives signals that it should go division again. During this interphase, a cell grows in size, becomes structurally and functionally active, and matures into a parent cell. Once a daughter cell is formed from the parent cell, the G 1 phase of the cell cycle starts. Recall that mitosis is a part of the normal cell cycle. The Cell Cycleīefore jumping to studying the various steps of mitosis, it is important to understand the pre-mitotic events that prepare a cell for mitosis. We will study various steps of mitosis, its regulation as well as its importance in living organisms. It is a process in which a nucleus divides into two daughter nuclei having the same number of chromosomes as the parent nucleus. Mitosis is a type of nuclear division that is a part of the normal cell cycle of most of the cells. Out topic of discussion in this article is mitosis. The division of the nucleus is of two types Meiosis and Mitosis. The process of cell division involves two essential steps, division of the cytoplasm and division of the nucleus. The process of cell division not only gives rise to a new life but is also responsible for transferring the traits of the parent cell into the daughter cells. It is the process by which new life comes into existence from a pre-existing cell. Cell division is a process of growth and reproduction at a cellular level. The process of cell replication and cell division is essential for the maintenance and continuity of life of an organism.
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