Question

With the help of suitable diagrams, explain the mitosis in detail.​

Answer 1

Explanation:

In cell biology, mitosis is a part of the cell cycle when replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which the number of chromosomes is maintained.In general, mitosis is preceded by the S stage of interphase and is often accompanied or followed by cytokinesis, which divides the cytoplasm, organelles and cell membrane into two new cells containing roughly equal shares of these cellular components.Mitosis and cytokinesis together define the mitotic (M) phase of an animal cell cycle—the division of the mother cell into two daughter cells genetically identical to each other.

The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are prophase, prometaphase, metaphase, anaphase, and telophase. During mitosis, the chromosomes, which have already duplicated, condense and attach to spindle fibers that pull one copy of each chromosome to opposite sides of the cell. The result is two genetically identical daughter nuclei. The rest of the cell may then continue to divide by cytokinesis to produce two daughter cells.Producing three or more daughter cells instead of the normal two is a mitotic error called tripolar mitosis or multipolar mitosis.Other errors during mitosis can induce apoptosis or cause mutations. Certain types of cancer can arise from such mutations.

Mitosis occurs only in eukaryotic cells. Prokaryotic cells, which lack a nucleus, divide by a different process called binary fission. Mitosis varies between organisms.For example, animal cells undergo an "open" mitosis, where the nuclear envelope breaks down before the chromosomes separate, whereas fungi undergo a "closed" mitosis, where chromosomes divide within an intact cell nucleus.Most animal cells undergo a shape change, known as mitotic cell rounding, to adopt a near spherical morphology at the start of mitosis. Most human cells are produced by mitotic cell division. Important exceptions include the gametes – sperm and egg cells – which are produced by meiosis.

Answer 2

Answer:

1. Mitosis is the process of cell division occurring in somatic cells and stem cells. It is essential for the growth of the body, restoration of emaciated body, wound healing, formation of blood cells, etc.
2. It is completed through two main steps namely, Karyokinesis ( nuclear division ) and Cytokinesis ( cytoplasmic division ).
3. Karyokinesis occurs via. four steps, i.e. prophase, metaphase, anaphase, and telophase.

• Prophase: During this phase thread like chromosomes condense. The centrioles duplicate and move to the opposite poles of the cells. The nuclear membrane and nucleolus start disappearing.
• Metaphase: During metaphase, the nuclear membrane completely disappears. Chromosomes complete condensation and become clearly visible along with sister chromatids. The chromosomes arrange parallel to the equatorial plane of the cell. Spindle fibres are formed between the centromere of each chromosomes and both the centrioles respectively.
• Anaphase: The centromere split and the sister chromatids are pulled apart in opposite directions with the help of spindle fibres. The separated sister chromatids ( daughter chromosomes ) reach to opposite poles of the cell.
• Telophase: Daughter chromosomes begin to decondense and the nuclear membrane is reformed around each set of chromosomes persent at the poles. This results in the formation of two daughter nuclei. The nucleolus reappears in each daughter nuclei. The nucleolus reappears in each daughter nucleus and the spindle fibres disappear completely.

1. 4. With the end of Karyokinesis, Cytokinesis begins and as a result two new daughter cells are formed.
2. 5. During Cytokinesis, a notch forms at the equatorial plane that gradually deepens to form two seperate cells. A cell plate is fromed in the centre of the cell instead of a notch in case of plant cells.