Mitosis
Mitosis is a type of cell division involves a series of complex changes in both, the nucleus and cytoplasm. During mitosis the diploid (2n) number of chromosomes kept constant in daughter cells.
Interphase
It is an active phase of cell division which occurs before the onset of mitosis. The basic components of cell duplicated during this phase particularly the DNA and histones. Moreover various proteins are also synthesized during interphase, which are essential for proper completion of mitosis.
Main Phases of Mitosis
The process of mitosis has been studied in both plants and animals. Walther studies it in animals wile Strassburger studied it in plants. According to these studies, mitosis takes place in somatic cells and comprises two phases.
1- Cytokinesis (division of cytoplasm)
2- Karyokinesis (division of nucleus)
Cytokinesis
Cytokinesis refers to the division of cytoplasm. In animals, it is carried out by the formation of cell membrane and contraction of cytoplasm. Cell membrane moves inward deeply and divides the cell into two halves. In plants, some special structures are formed by the transformation of spindle fibers at equatorial; these structures are called phragmoplast which leads to the division of one cell into two.
Karyokinesis
Karyokinesis refers to the division of nucleus. It comprises four stages:
1- Prophase
2- Metaphase
3- Anaphase
4- Telophase
1- Prophase
It involves the appearance of chromosomes as thin threads by the condensation of chromatin fiber in the nucleus. Each chromosome comprises two chromatids with centromere present in between. As mitosis proceeds, nucleolus and nuclear membrane also disappears gradually
2- Metaphase
During this phase spindle fibers starts to appear. Chromosomes get attached with spindle fibers and migrates from equator to opposites poles to take the final shape.
3- Anaphase
During anaphase, Spindle fibers attached to centromere pull them and two chromatids get separated from each other and move towards opposite poles.
4- Telophase
This phase is an opposite or reversal phase of prophase. All changes took place during prophase reverse to their original states. On reaching the poles, chromosome start uncoiling and nucleoli and nuclear membrane begins to appear, which results in the formation of two daughter cells.
Significance of Mitosis
Mitosis is a significant cell division which ensures the provision of correct and complete genetic information to the daughter cells. As chromosome have heredity material and number of chromosomes must be kept constant in daughter cells in order to transfer complete genetic information and mitosis keeps this number of chromosome constant. In case of abnormal number of chromosome, several physiological and psychological disorders can cause in an organism. So we can say that the product of mitosis is not only quantitative but qualitative as well. Healing of wounds and formation of new cells takes place due to the process of mitosis.
Mitosis is a type of cell division involves a series of complex changes in both, the nucleus and cytoplasm. During mitosis the diploid (2n) number of chromosomes kept constant in daughter cells.
Interphase
It is an active phase of cell division which occurs before the onset of mitosis. The basic components of cell duplicated during this phase particularly the DNA and histones. Moreover various proteins are also synthesized during interphase, which are essential for proper completion of mitosis.
Main Phases of Mitosis
The process of mitosis has been studied in both plants and animals. Walther studies it in animals wile Strassburger studied it in plants. According to these studies, mitosis takes place in somatic cells and comprises two phases.
1- Cytokinesis (division of cytoplasm)
2- Karyokinesis (division of nucleus)
Cytokinesis
Cytokinesis refers to the division of cytoplasm. In animals, it is carried out by the formation of cell membrane and contraction of cytoplasm. Cell membrane moves inward deeply and divides the cell into two halves. In plants, some special structures are formed by the transformation of spindle fibers at equatorial; these structures are called phragmoplast which leads to the division of one cell into two.
Karyokinesis
Karyokinesis refers to the division of nucleus. It comprises four stages:
1- Prophase
2- Metaphase
3- Anaphase
4- Telophase
1- Prophase
It involves the appearance of chromosomes as thin threads by the condensation of chromatin fiber in the nucleus. Each chromosome comprises two chromatids with centromere present in between. As mitosis proceeds, nucleolus and nuclear membrane also disappears gradually
2- Metaphase
During this phase spindle fibers starts to appear. Chromosomes get attached with spindle fibers and migrates from equator to opposites poles to take the final shape.
3- Anaphase
During anaphase, Spindle fibers attached to centromere pull them and two chromatids get separated from each other and move towards opposite poles.
4- Telophase
This phase is an opposite or reversal phase of prophase. All changes took place during prophase reverse to their original states. On reaching the poles, chromosome start uncoiling and nucleoli and nuclear membrane begins to appear, which results in the formation of two daughter cells.
Significance of Mitosis
Mitosis is a significant cell division which ensures the provision of correct and complete genetic information to the daughter cells. As chromosome have heredity material and number of chromosomes must be kept constant in daughter cells in order to transfer complete genetic information and mitosis keeps this number of chromosome constant. In case of abnormal number of chromosome, several physiological and psychological disorders can cause in an organism. So we can say that the product of mitosis is not only quantitative but qualitative as well. Healing of wounds and formation of new cells takes place due to the process of mitosis.
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