Difference Between Mitosis and Meiosis in Cell Division

The main difference between the processes of mitosis and meiosis is determined by the function that each process performs. In a general sense we can say their functions are the following:

• Mitosis: the division of the nucleus of any cell of an organism (somatic cells). It is necessary for the growth and renewal of said cells. It also plays a key role in maintaining genetic consistency across generations of cells.
  
  
• Meiosis: is carried out only and exclusively by the cells involved in the reproduction process. It has the the aim of exchanging genetic information between the nuclei of two sex cells from different organisms. In doing so, it increases the genetic diversity and survival of the species. This genetic variation is crucial for the process of natural selection and evolution.

Not only do mitosis and meiosis have different functions, but the type of cell is different. We can see this reflected in the differences between the number and type of chromosomes or genetic material that are involved in these cell division processes. This is the difference between mitosis and meiosis with respect to the types of cells involved:

• Mitosis: short-lived process involving haploid (n) cells with unpaired chromosomes. This process ensures that each daughter cell retains the same chromosome number as the parent cell, thus preserving genetic stability.
  
  
• Meiosis: long process involving diploid (2n) cells with paired chromosomes. It results in the production of gametes that have half the number of chromosomes, which is vital for sexual reproduction.

As stated in the introduction, one of the main differences between mitosis and meiosis is the type of cell which is created. These two types of cell division create the following types of cells:

• Mitosis: after a single cell division, two new daughter cells genetically identical to the mother cell are obtained. This happens because the exchange of genetic information between chromatids has not occurred. This uniformity is essential for the repair and replacement of tissues in multicellular organisms.
  
  
• Meiosis: after undergoing two nuclear fissions, the original cell gives rise to four final gametes (sex cells), each having half the number of chromosomes contained in the original cell. In addition, these four new cells have different genetic information, since during the meiosis process they have undergone a genetic exchange, known as crossing over^[1]. This variation is critical for the adaptation and survival of species in changing environments.

Learn more about how we know the differences between mitosis and meiosis in our article where we ask why is the study of cells so important?

Although they are different processes, both mitosis and meiosis are types of cell division. The reason we want to create a comparison between mitosis vs. meiosis is due to their similarities, the most important of which include:

• Cell nucleus division process: thanks to both biological phenomena, living beings guarantee their survival. Mitosis does this through the growth and maintenance of their own cells and tissues. Through meiosis, the cells guarantee the diversity and genetic balance between species. With such genetic diversity in the gametes, the consequent organisms are better able to survive and adapt to various environmental pressures.
  
  
• Universality: the existence of the processes of mitosis and meiosis is universal, occurring with a greater or lesser frequency in all eukaryotic living beings that exist on the Earth. This universality underscores the significance of these processes in the continuity and evolution of life.

Learn more about how these processes affect living beings with our guide to the difference between eukaryotic and prokaryotic cells.

To better understand the differences between mitosis and meiosis, it can be helpful to look at each process of cell division individually. In its basic sense, we can say the definition of mitosis is:

The biological process by which the somatic cells of eukaryotic living organisms divide their cell nucleus and the genetic information available to them.

In this way, living organisms guarantee their survival, thanks to the correct growth and maintenance of all their cells. Both animal cells and those of plants, fungi and other eukaryotic microorganisms carry out the amazing process of cell mitosis. This process is fundamental for healing wounds and replacing dead or damaged cells.

To achieve an equitable distribution of DNA or genetic material, there are five main phases of mitosis. They are the following:

1. Interphase: a preparatory phase where the cell grows and duplicates its DNA.
2. Prophase: chromosomes condense and become visible, and the nuclear envelope begins to disintegrate.
3. Metaphase: chromosomes align in the center of the cell, attached to spindle fibers.
4. Anaphase: sister chromatids are pulled apart to opposite ends of the cell.
5. Telophase: nuclear membranes reform around the separated chromatids, and the cell begins to split.

The final result of mitosis is to obtain two daughter cells with identical genetic information. These are identical both between them and with respect to the mother cell. In this way, mitosis constitutes a type of asexual reproduction in which no more than a single stem cell is involved. This form of reproduction is crucial for the propagation of species that reproduce asexually. You can learn more about these different processes with our guide to asexual reproduction in plants and animals.

Meiosis is the most important process responsible for guaranteeing genetic diversity among individuals of the same species. This amazing biological process is necessary to carry out sexual reproduction between organisms of different sexes. In this way, meiosis is responsible for producing the male (sperm) and female (ovules) sex cells necessary for sexual reproduction. The result is the creation of new individuals genetically different from their parents, contributing to the rich tapestry of life.

During the complex genetic process of meiosis, two successive divisions of the cell nuclei are carried out. This is because the process is long and entails the completion of the following stages of meiosis:

Meiosis I

• Prophase I: homologous chromosomes pair up and exchange genetic material through crossing over.
• Metaphase I: paired homologous chromosomes align at the cell equator.
• Anaphase I: homologous chromosomes are pulled to opposite poles.
• Telophase I: the cell divides into two, each with half the original chromosome number.

Meiosis II

• Prophase II: chromosomes re-condense, and a new spindle forms.
• Metaphase II: chromosomes align again at the equator, but now as separate entities.
• Anaphase II: sister chromatids are finally separated.
• Telophase II: four distinct haploid cells are formed after the final cell division.

After the division and exchange of genetic material, the four cells resulting from the meiotic process are characterized by being haploid, i.e. there is a single copy of the genetic material. In doing so, they provide new genetic information which is enriched and more varied. This can help the organism adapt better to their environment, have a better chance of fighting disease, and provide many benefits science is yet to discover. The genetic shuffling during meiosis is fundamental for evolution, as it introduces new genetic combinations into populations.

Now that you know well the difference between mitosis and meiosis, you can learn more about these processes with diagrams of the cell division cycle.

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