It is a type of cell division in which the number of chromosomes in the daughter cell remains constant as in the mother cell. It is also known as somatic cell division or somitogenesis. The process of mitosis is almost similar in both animal and plant that take place during embryonic development and growth. Although mitosis is a continuous process, for better understanding it can be divided into two phases, namely Karyokinesis and Cytokinesis.
KARYOKINESIS: it is the division of the nucleus, which involves further four stages or phases:
- Prophase: prophase includes the following characters:
- During the early stages of the cell cycle, chromosomes are not clearly visible even under the electron microscope.
- As prophase proceeds, fine threads of chromosomes appear in form of the network called chromatin
- Later on, chromosomes get condensed and become more visible having two chromatids attached at the point called the centromere.
- In the late prophase, the nuclear membrane starts to disappear and the nucleolus also disappears.
- Finally, all the nuclear material gets free in the cytoplasm and mitotic apparatus start to originate. Aster and spindle collectively called Mitotic apparatus. It contains different types of fiber: Continuous Fibers are the fibers which run from pole to pole; Discontinuous Fibers are those fibers that run from central region or central poles; Astral Fibers are those fibers are short radiating from centrioles and remain at the pole.
- Metaphase: Metaphases have the following features:
- At the beginning of this stage, the nuclear membrane completely disappeared and nuclear material arranged itself in the cytoplasm.
- In this phase, chromosomes become more prominent and the region of centromere known as Kinetochore appeared with the special fibers known as kinetochore fibers.
- The chromosomes arrange themselves on the equatorial plane with spindle fiber radiating from poles.
- The spindle fiber that is attached to the kinetochore, starts to contact and move toward the pole.
- As a result of contraction, chromatids become detached at the point of centromere and now served as chromosomes.
- In the end, chromosomes are pulled to the opposite poles by further contraction of fiber.
- Telophase: This is the last phase of karyokinesis and is known as the reverse of prophase. It has the following main features
- Chromosomes start to coiling and form a chromatin network. In the late telophase, two-daughter nuclei are formed.
- The nuclear membrane reappeared and nucleolus and other organelles start to reappear.
CYTOKINESIS: It is the division of the cytoplasm, as a result of which two daughter cells are formed
- During late telophase, the astral microtubules end signals to the equatorial region of the cell.
- At this point, actin and myosin are activated form the contractile ring.
- Later on cleavage, furrows developed at the center that deepens towards the center of the cell and finally, two daughter cells are formed.
As a result of mitosis, two daughter diploid cells arise from the division of diploid mother cells. This is a sample essay written for our client to get a customized essay or research paper contact us at Essay Mills.