Diagram of Mitosis represents the process of cell division where a cell replicates its chromosomes and separates them into two identical nuclei. It occurs in all living organisms including aquatic plants and algae and forms two genetically identical daughter cells. The process of mitosis is divided into four main stages: prophase, metaphase, anaphase, and telophase. Mitosis is essential for organisms’ growth and development, repairing damaged tissues and replacing worn-out cells. In this article, we will study mitosis in detail with a well-labeled diagram, its stages, and functions.
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Mitosis
Mitosis is the process of cell duplication or reproduction. The term mitosis means “threads”and represents the threadlike appearance of chromosomes during the process of cell division. The process results in the formation of two genetically identical daughter cells, each with the same number of chromosomes as the parent cell. It contrasts with meiosis, another type of cell division that produces gametes (sperm and egg cells) with half the chromosome number for sexual reproduction.
Mitosis succeeds the G2 phase and is followed by cytokinesis where the cytoplasm divides after the separation of the nucleus. It has five phases: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis forms the basis of sexual reproduction and is important for the growth and development of the embryo.
Diagram of Mitosis
A diagram of Mitosis showing the different stages is as follows:
Stages of Mitosis
During mitosis two identical daughter cell are produced from one cell. It maintains an equal number of chromosome in each daughter cell after division. It consists of five different stages:
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
Before the cycle of mitosis starts the cell remains in the interphase stage. In interphase the cell prepare itself for the cell division. Duration of the interphase is around 90% of the total cell cycle. During this phase, DNA replicates and the cell grows. Interphase has three further phases:
- G1 Phase: The cell undergoes growth
- S Phase: The DNA of the cell replicates.
- G2 Phase: The cell continues to grow and prepare for cell division
The stages are described in detail as follows:
Prophase
It is the first and longest phase of mitosis. It is characterised by the condensation of nuclear genetic material.
- Chromatin consisting of DNA and protein molecule in the nucleus condenses.
- The nuclear membrane and nucleolus start to disappear.
- Centrioles duplicate and move to the opposite poles of the cell.
- Spindle fibers begin to form, extending from the centrosomes.
Prometaphase
It is a transitional phase between prophase and metaphase. The cell prepares for the alignment and separation of chromosomes.
- Nuclear envelope breakdown completely into numerous membrane vesicles.
- Chromosomes present inside form protein structures called kinetochores.
- Microtubules attach to the kinetochore part of chromosomes facing the opposite mitotic poles. It ensures equal separation and distribution to the dividing daughter cells.
Metaphase
The term metaphase is a Ancient Greek word where meta means ” beyond, above, transcending” and phásis means appearance. Th stage is characterised by chromosomes become aligned at the metaphase plate or equatorial plane of the cell.
- At this stage chromosome are at the second most condensed and coiled stage.
- The spindle fibers attach to the centromeres of chromosomes. It ensures proper alignment for proper distribution of genetic material during the succeeding stages.
- It takes 4% of the cell cycle duration.
Anaphase
The term anaphase is derived from ancient Greek word ‘ana’ meaning “back or backward” and phásis means appearance. Anaphase is characterised by chromosome separating or moving towards opposite poles of the cell.
- Kinetochore microtubules shorten.
- Chromosome reach their maximum condensation during late anaphase. It help in chromosome segregation and nucleus reformation.
- Homologous chromosomes move towards opposite spindle poles
- Non-kinetochore microtubules lengthen
- Centrosomes are pushed far apart and cell elongates
- Ensures each daughter cell gets an identical set of chromosomes.
Telophase
The term is telophase is derived from Ancient Greek word telos meaning ” end, result or completion” and phásis means appearance. In this phase the chromosome have arrived at the opposite poles and nuclear envelope reforms.
- Chromosome condensation starts and unwind back into chromatin.
- Nuclear envelope forms around each set of chromosomes
- Spindle starts disappearing
- Nucleus forms around each set of daughter chromosomes
- It takes around 2% of the cell cycle time.
- After telophase, the cytokinesis process occurs, resulting in the formation of 2-4 daughter cells.
Functions of Mitosis
Functions of mitosis includes:
- Mitosis allows the growth and development of an organism. For example, the zygote divides to form genetically identical daughter cells through the process of mitosis.
- Mitosis repairs cells during wound healing.
- It replaces or regenerate damaged cells in the body.
- Mitosis is a type of asexual reproduction
- It ensures each cell receives an identical set of chromosomes, maintaining genetic stability.
- Provides continuity of genetic information from one generation of cells to the next.
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FAQs on Mitosis
1. Define Mitosis.
Mitosis is a type of cell division that results in the production of two genetically identical daughter cells. The DNA of the cell’s nucleus is split into two equal sets of chromosomes.
2. Why is Mitosis Called Equational Division?
Mitosis is called equational division as it results in the formation of two genetically identical daughter cells with the same chromosome number as present in the parent cell. It ensure maintaining genetic stability.
3. What Happens in Metaphase?
Metaphase is the second stage of mitosis in which the chromosome align itself on the metaphase plate in the centre of the eukaryotic cell. They start to separate into individual chromatids and move towards opposite poles.
4. What is the Primary Function of Mitosis?
The primary function of mitosis includes growth and development of the cells. It repairs the cell during injury and replace the old cells of the body. It also plays an important role in the regeneration of the damaged tissues or cells.