Every day, per second, cells divide and give rise to new cells in the body. One cell produces two, two produces four, four produces eight, and it continues. Cell division occurs through two ways – mitosis and meiosis, depending on the type of cell.
Cell division is important for life functions, growth, and development. Mitosis and meiosis follow different processes. The focus of this article is mitosis – its function and significance in living cells, among many other important details.
At the end of this article, you will understand what goes down in the process of replacing your hair, skin, and fingernails.
What is mitosis cell division?
Mitosis is a type of cell division that somatic (non-reproductive) cells undergo to carry out growth, repair, and maintenance.
In mitosis, a newly formed DNA separates into two cells with the same number of chromosomes and parent nucleus. Also, the nucleus of the parent cell splits into two identical nuclei. This is crucial to the growth of new cells and the replacement of worn-out cells.
For instance, mitosis in plants is responsible for the growth of vegetative parts like the shoot buds, root tips, and stem tips.
Stages of mitosis
Mitosis occurs through four phases: prophase, metaphase, anaphase, and telophase.
In prophase, centrioles migrate, the spindle fibers are formed, the nuclear envelope and nucleolus disintegrate, and the chromatin fibers condense.
However, the process is slightly different in plant and animal cells. Plant cells do not undergo the migration of centrioles because they do not have these organelles. The disintegration of the nuclear envelope and nucleolus and chromatin condensations occurs in plant and animal cells.
Afterward, the cycle continues with the metaphase where spindle fibers attach to the centromere of each chromosome and prepare it for segregation.
In the metaphase, all chromosomes arrange themselves for the anaphase, which involves the contraction of the spindle fibers and separation of sister chromatids (the halves of the chromosomes) to form daughter chromosomes.
Also, in the metaphase, the separated chromatids migrate to opposite poles of the spindle fibers and the cell elongates. In the anaphase, the cytoplasm of the parent cell begins to divide into two daughter cells.
By the last phase of mitosis, telophase, each set of daughter chromosomes reaches the opposite poles of the cell and forms a new nuclear membrane. Also, cytokinesis ends, and the daughter cells separate, each having its nucleus and cytoplasm.
What are the functions of mitosis in eukaryotes?
- It allows the multicellular organism to maintain its tissues, skin cells, and blood is an example.
- Mitosis is at the core of the growth and development of eukaryotes
- This form of cell division helps to repair damaged tissues
- The mitotic process ensures the maintenance of a constant number of chromosomes in the daughter cells
- It helps to maintain the proper size of the cells
- In unicellular organisms, mitosis is the process of asexual reproduction
Why is mitosis important?
1. This is the core of life
Mitosis produces new cells that contain the exact genetic information of the parent cell. These new cells come together to form new tissues and organs or repair damaged tissues and organs. Without this process, plant and animal life will be discontinued.
For instance, red blood cells have a lifespan of four months and new ones can only be produced by mitosis. Also, the production of new cells is necessary for the adaptability and survival of plants and animals in new environments.
2. No mitosis, no growth and development
After the fusion of two gametes (from meiosis) to produce an embryo, mitosis continues the process of growth and development. By this process of cell division, one cell gives rise to many other cells that form a complex multicellular organism.
Mitosis is the basis of growth and development in plants. New cells give rise to new leaves, stems, roots, and a bigger and more mature plant. It is also crucial to the repair and replacement of damaged or worn-out cells, which will self-destruct or lead to cancer if left alone.
3. Tissue regeneration and wound healing
Wound healing and tissue regeneration stem from mitosis. Cells make up tissues. When you get cuts or injuries, there could be tissue damage. The cells around the site of injury divide and form new cells that replace the damaged or lost cells.
This is the beginning of healing, repair, and tissue regeneration. This is the underlying mechanism behind the healing of fractures. All living organisms – plant and animal – use mitosis to replace damaged or lost body parts.
4. Asexual reproduction
Budding in hydra and fragmentation in planaria are forms of asexual reproduction that use the mitotic process to produce identical offspring. These organisms can reproduce sexually or asexually, depending on the abundance of materials in their environment.
They employ sexual methods in scarcity and asexual methods in abundance. The parent cell divides into new daughter cells with identical genetic information. Many plants, fungi, and some invertebrates employ asexual reproduction to produce offspring.
5. DNA repair
DNA can be damaged by UV radiation or metabolic processes. Naturally, DNA replication occurs during mitosis and if damages are not fixed, they will be replicated, and mutations can occur.
However, to avoid this, mitosis looks for a way to fix this damage and prevent mutations that can lead to diseases.
During mitosis, the cell checks its DNA for damage. Rather than using the whole strand as a template for replication, it picks an undamaged sequence and uses it instead. This way, it produces new healthy cells with correct genetic information.
6. Maintenance of homeostasis
Homeostasis is a self-sustaining process that helps keep all body systems balanced to ensure survival and proper functioning, even in adverse conditions.
Through cell division and the replacement of old and worn-out cells with new ones, mitosis supports the overall aim of homeostasis. It ensures proper body functions and helps to keep the internal environment stable regardless of the influence of external stimuli.
7. Correct duplication of genetic information
The essence of reproduction is that the daughter cells are identical to the parent cells and mitosis ensures this. Mitosis ensures that the new cells have the same genetic information as the parent cell and can carry out the same functions.
This process is critical to maintaining the overall integrity of the genetic code of the organism. It is also important to the replacement of damaged or lost cells, and for proper tissue and organ function.
Furthermore, mitosis reduces the chances of mutations during the copying of the genetic material. Cells have an in-built error control mechanism that corrects any errors that happen during the duplication of genetic material.
Mitosis ensures that each new cell can differentiate and form the same cell as the parent cell. It also prevents the build-up of harmful mutations that could be the onset of disorders and diseases.
8. Cell differentiation
Cell differentiation is another reason why mitosis is important to living organisms. The development stage of organisms involves the formation of different and specialized cell types. The new formed through mitosis differentiate into the specialized cell types.
Some of these specialized cell types are muscle cells, skin cells, blood cells, liver cells, nerve cells, etc.
9. Immune system support
By producing more cells from a single parent cell, mitosis ensures that the body has enough cells to defend itself against attacks from microbes like bacteria and viruses.
When a microbe enters the body, there is a signal for lymphocytes to begin cell division and produce new cells to wade off an impending infection. Since mitosis ensures that daughter cells have the same genetic material as the parent cell, the new cells can recognize the invader and attack it.
Immune response increases with increasing number of lymphocytes. Without mitosis, fighting off infection would be delayed or impossible.
Also, mitosis helps to replace worn-out, damaged, or lost cells with new, healthy ones via a self-repair process. The damaged cell divides into new cells and continues until there are sufficient new, healthy cells. Afterward, the damaged cells are removed by apoptosis.
This process helps to prevent diseases from spreading through the body, enhances organ functioning, boosts overall health, and reduces signs of aging.
10. Regulation of cell number
Cell division occurs during embryogenesis and regulates cell number to ensure the proper function of organs after birth. If too many or too few cells divide in the stage of embryogenesis, there could be developmental disorders in the fetus such as Down Syndrome.
Mitosis works to ensure that the right number of cells divide. Keeping the cell number within the optimal range also plays a crucial role in the growth and development of infants after birth and the replacement of damaged skin cells.
Is there a link between mitosis and cell death?
Apoptosis or cell death is the pre-planned demise of cells that occurs as part of natural growth. Mitosis, a type of cell division, is a process that gives rise to identical cells.
When cell division becomes detrimental to the overall well-being of the organism, the cell cycle regulators signal for apoptosis if the cell cannot exit mitosis. If this does not happen, cell division will continue and could lead to cancer.
Apoptosis naturally occurs in old, worn-out cells. The body intentionally removes them to make room for new young cells. There must be a regulation and balance between mitosis and apoptosis. Otherwise, there would be damaged and cancerous cells, or good and healthy cells would be eliminated.
What happens if mitosis goes wrong?
During the process of cell division, if the chromosomes do not split into two halves, the new cells will have either an extra chromosome or be missing some chromosomes. This error usually occurs during pregnancy and causes chromosome abnormalities in the babies.
Chromosomal aberrations are the causes of genetic disorders and developmental abnormalities seen in some children. It also affects the normal physiological processes of tissues and organs and causes diverse health issues.
Mitotic errors are responsible for genetic mutations that occur during DNA replication. An accumulation of genetic disorders and chromosomal aberrations can increase the risk of cancer. Cancer also occurs when cells divide uncontrollably and abnormally and eventually form tumors.
Other consequences of mitotic errors are impaired tissue repair and delayed recovery from injuries, genomic instability, and autoimmune diseases such as lupus and multiple sclerosis.
FAQs
Does mitosis occur in all cells of the human body?
Mitosis occurs in all cells of the human body except reproductive cells. This is because the process of mitosis does not involve crossing over, so there is no expression of new traits. Reproductive cells are produced through meiosis which allows the expression of new traits.
How do cells regulate mitosis?
Cells regulate mitosis using cell cycle regulators called mitotic kinases. The most active regulator is the CDK1, one of the CDK cell regulators. CDK1 forms complexes with mitotic cyclins A & B (binding partners) which drive the cells into mitosis.
The control of CDK1/cyclin B activity is essential for the progression and exit of the mitotic process. The destruction of cyclin B turns off the activity of CDK1 and causes the cell to exit mitosis.
Parent cells communicate via the cyclins. Cyclins are proteins that signal cells, telling them when to start and stop dividing. Regulation of mitosis is essential for preventing the onset of cancer.
Are there any similarities between mitosis and meiosis?
Mitosis and meiosis occur in the nuclei of the cell and DNA synthesis occurs in both processes. Also, they both occur in the M-phase of the cell cycle and have the same basic stages: prophase, metaphase, anaphase, and telophase.
Additionally, in both processes of cell division, cytokinesis occurs in the telophase stage of the cell cycle.
Conclusion
Mitosis is an asexual process that enables living organisms to grow, develop, and reproduce. This form of cell division is at the core of various cell functioning and survival in eukaryotes. Mitosis is a process whereby an organism can regenerate cells without reducing their chromosome set.
So, mitosis is behind the replacement of skin cells and organs in the body. This is the explanation behind healing after sustaining injuries. The rate of mitosis in cells depends on the type and function of the cell.
Without this process, tissues and organs will not be healthy, and will not function as they normally would.
Also, learn about the significance of meiosis and likely errors that could happen.
Thanks for reading.