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Explanation Of Mitosis
Mitosis is a type of cell division that creates two new cells each like the original one carrying the same number of chromosomes as that of parent cells. The two new cells are formed when the parent cells undergo division.
This process carries a key significance in biology as it helps in cell growth, repairing of damaged tissues and also helps in asexual reproduction.
In this article we will be covering its stages, its importance and commonly asked questions related to the topic.
Features of Mitosis
In mitosis, the chromosomes replicate and then are divided equally between the two daughter cells. The nuclear envelope also reforms around the chromosomes. The process of mitosis is divided into five phases: prophase, metaphase, anaphase, telophase, and cytokinesis.
Functions of Mitosis
Mitosis is a process of cell division in which a single parent cell divides into two genetically identical daughter cells. The process of mitosis is divided into five phases: prophase, metaphase, anaphase, telophase, and cytokinesis.
- During prophase, the nuclear envelope breaks down and the chromosomes condense into thick strands. The mitotic spindle begins to form, and the chromosomes attach to the spindle fibers.
- During metaphase, the chromosomes are arranged in the middle of the cell and the spindle fibers extend to the opposite ends of the cell.
- During anaphase, the chromosomes are pulled apart and move to the opposite ends of the cell.
- During telophase, the chromosomes uncoil and the nuclear envelope reforms.
- During cytokinesis, the cytoplasm divides and the daughter cells are formed.
What is the Simple Definition of Mitosis?
Mitosis is a process of cell division where a single cell divides to form two identical daughter cells each carrying the same number of chromosomes as that of the original one.
This process is important as it ensures that each new cell has the same genetic information as the one before it.
Equational Division
This process is also known as equational division as the number of chromosomes in the daughter cells remains the same as the parent cell.
Like if the parent cell carries 46 chromosomes, i.e, 23 pairs then the daughter cells produced after the cell division will also be having 46 chromosomes.
This ‘equal’ division ensures that the genetic material from the parent cell is correctly copied and distributed evenly in the daughter cell, which is why it’s called equational division.
What are the 4 Stages of Mitosis?
Mitosis is a crucial process that ensures accurate cell division. The process is carried out precisely in 4 stages. It is preceded by Interphase where the cell pre[pares for division by replicating its DNA.
Interphase
Interphase has 3 steps-
- G1 Phase
- S Phase
- G2 Phase
After Interphase, the cell enters the mitosis which is divided into 4 stages:
- Prophase
- Metaphase
- Anaphase
- Telophase
The above four stages combined together are called M-Phase.
Mitosis Phases
As we discussed above, Mitosis occurs in 4 distinct stages that is preceded by the interphase. Let’s take a deeper look into all the processes and understand the mechanism of Mitosis.
So before mitosis starts, the cell undergoes a preparatory phase, i.e, the Interphase where the cell duplicates its DNA. Lets understand interphase-
THE INTERPHASE
Interphase is a long non-dividing phase between two successive M-Phase. Therefore it’s often called the resting phase or the preparatory phase. This phase alone takes up 95% of the time of the cell cycle.
During interphase the cell prepares itself for cell division by undergoing both DNA duplication and cell growth. It is divided into 3 subphases-
- G1 PHASE:
- This phase is also known as GAP1 PHASE.
- During this phase the cell is metabolically active (except mitochondria, chloroplasts, centriole)
- The cell grows
- Protein is synthesised
- RNA is produced.
- During this phase more enzymes.
- This phase prepares itself for DNA replication.
- S PHASE:
- This phase is called Synthesis Phase.
- DNA replication takes place in the nucleus during this phase.
- The centriole duplication takes place in the cytoplasm.
- Two identical sets of chromosomes are created.
- It ensures that each daughter cell gets a complete set of genetic material.
- G2 PHASE:
- It is also known as GAP2 PHASE.
- This process is marked by the synthesis of protein and cell growth.
- Necessary proteins and organelles are produced.
- Prepares the cell for the cell division process.
After interphase, the cell enters the Mitosis or the M- Phase.
THE MITOSIS
It is usually known as the most dramatic period because of the significant and visible changes that occur in the relatively short period of time. This contributes just 5% of the entire cell cycle.
During Mitosis the single cell divides to form 2 daughter cells, which involves a series of well coordinated 4 stages:
- PROPHASE:
- It is the longest phase of the M-phase.
- The DNA condenses into visible chromosomes, each having two sister chromatids.
- The nuclear envelope starts breaking down and gradually disappears.
- The formation of mitotic spindles that are made up of microtubules starts from the centrosome moving to opposite sides of the cells.
- This phase is crucial for organising the chromosomes and preparing them for alignment.
- METAPHASE:
- The chromosomes line up at the centre of the cell which is called the metaphase plate.
- Spindle fibres attach to the centromere.
- This ensures the chromosomes are properly positioned for the separation.
- ANAPHASE:
- Splitting of centromeres takes place.
- Spindle fibres pull the sister chromatids apart to the opposite parts of the cell.
- This ensures each new cell receives the identical set of chromosome.
- This has the shortest duration.
- TELOPHASE:
- Chromosomes condense into long fine filaments.
- Spindle fibres diapers and replication of centriole takes place.
- Nuclear envelope reforms around the chromosome.
- Nucleolus, Golgi complex, and endoplasmic reticulum reappear.
CYTOKINESIS
Although not technically a part of mitosis, it is accomplished by the division of the parent cell into two daughter cells by the separation of cytoplasm into each daughter cell via the process of Cytokinesis.
Importance of Mitosis?
Mitosis has several important biological functions. It has functions that are important to the development of organisms, as its product increases cellularity.
- This mitosis is essential for the repair of wounds and other damaged tissue.
- Mitosis also enables some organisms to reproduce asexually, without the need for a mate.
- Another important feature of mitosis is that it rapidly and accurately distributes, to daughter cells.
- They are an identical copy of the parent cell’s genome helping prevent DNA loss across generations thus conserving genetic stability.
FAQs on Mitosis
What is mitosis?
Mitosis is the type of cell division where two daughter cells are produced from a parent cell, and they contain the same number of chromosomes as their parents. This is also known as equational division.
What are the 3 main purposes of Mitosis?
Mitosis is necessary for growth, repair and asexual reproduction. In unicellular organisms, we see that mitosis is a form of well-thought-out non-sexual propagation.
What are the stages of Mitosis?
The process begins with prophase, where the chromosomes condense and become visible, the nucleolus disappears, and the nuclear envelope starts to break down. Following this, prometaphase occurs, characterized by the disintegration of the nuclear envelope, allowing spindle fibers to attach to the kinetochores at the centromeres of the chromosomes. In metaphase, the chromosomes align at the cell's equatorial plane, known as the metaphase plate, with each sister chromatid connected to spindle fibers from opposite poles. Next is anaphase, where the cohesin proteins holding the sister chromatids together are cleaved, allowing them to be pulled apart toward opposite poles of the cell. This is followed by telophase, during which the separated chromosomes reach the poles, begin to decondense, and are surrounded by a reformed nuclear envelope. Finally, cytokinesis occurs, dividing the cytoplasm and organelles, resulting in two genetically identical daughter cells. This orderly sequence of events is crucial for maintaining genetic stability and proper cellular function.
Who is the father of Mitosis?
The father of mitosis is the German biologist Walther Flemming who made his greatest contributions to the understanding of cell division in the late 19th century.
Is mitosis haploid or diploid?
Mitosis can only happen in diploid cells, and the result will be two identical daughter cells that are also diploids meaning they have a correct number of chromosomes.
