Revised Definition Assignment – “Meiosis”

Introduction
The assignment task is to pick a complex term and compose a parenthetical, sentence, and expanded definition to an audience of non-technical readers based on a chosen situation. The objectives of this assignment include understanding the importance of definitions in technical writing and recognizing how certain audiences and purposes indicate the need for definitions. Other objectives include distinguishing and selecting the appropriate level of detail of a definition based on the situation.

Reading Situation
A geneticist is explaining the term ‘meiosis’ to a patient.

Parenthetical definition
The geneticist explains how meiosis (a type of cell division that produces specialized cells for reproduction) is important for sexual reproduction.

Sentence definition
Meiosis is a type of cell division (a process that divides one cell into two cells) in which the number of chromosomes (structures that store DNA in a cell) are halved to produce sex cells (specialized cells for sexual reproduction) (Mercier et al., 2015).

Expanded definition
Meiosis is a type of cell division (a process that divides one cell into two cells) in which the number of chromosomes (structures that store DNA in a cell) are halved to produce sex cells (specialized cells for sexual reproduction). This type of cell division involves one round of chromosome duplication (a process that creates a copy of each chromosome) and two rounds of cell division (Mercier et al., 2015).

Etymology

Meiosis originates from the Greek word meioun, which means “to lessen”. This refers to how the number of chromosomes in the cells produced by meiosis are reduced to half their original amount (Bolcun-Filas & Schimenti, 2012). This reduction of chromosomes is important as two sex cells, one from each parent, will combine their chromosomes during sexual reproduction and maintain the appropriate amount of DNA for their offspring (child).

Analysis of Parts

To gain a better understanding of how meiosis works, consider its main three parts:

1. Interphase – Before meiosis is initiated, the cell grows to the appropriate size and undergoes chromosome replication. The cell has two sets of chromosomes at this stage, with each individual chromosome attached to a duplicate chromosome from replication.
2. Meiosis I (Meiosis One) – The cell divides into two cells with half of the amount of chromosomes. Each cell now has one set of chromosomes at the end of this stage, with each individual chromosome still attached to a duplicate chromosome from replication.
3. Meiosis II (Meiosis Two) – The two cells each divide, producing four cells. Each cell is still has one set of chromosomes at the end of this stage, with the duplicate chromosomes now separated.
   The three main stages of meiosis can be visualized in Figure 1.

Visual

Figure 1: The three main stages of meiosis: Interphase, Meiosis I, and Meiosis II. Interphase results in each chromosome having a duplicate from replication. Meiosis I results in two cells with one set of chromosomes with the attached duplicate chromosomes. Meiosis II results in four cells with one set of chromosomes with the duplicate chromosomes now separated. Source: https://en.wikipedia.org/wiki/Meiosis

Contrast

Meiosis may be mistaken for the other type of cell division called mitosis, but there are important differences between meiosis and mitosis. While meiosis functions to create sex cells, mitosis functions to divide somatic cells (non-sex cells) (Sato et al., 2021). Meiosis involves two cell division steps and results in four cells each with one set of chromosomes, while mitosis involves one cell division step and results in two cells each with two sets of chromosomes.

Conclusion

Meiosis is a type of cell division that produces sex cells by reducing the number of chromosomes in half. It has three main stages; Interphase, Meiosis I, and Meiosis II. Meiosis can be differentiated by the other type of cell division, mitosis, by contrasting their function and final products.

References

Bolcun-Filas, E., & Schimenti, J. C. (2012). Genetics of meiosis and recombination in mice. International review of cell and molecular biology (pp. 179-227). Elsevier Science & Technology. https://doi.org/10.1016/B978-0-12-394309-5.00005-5

Mercier, R., Mézard, C., Jenczewski, E., Macaisne, N., & Grelon, M. (2015). The molecular biology of meiosis in plants. Annual Review of Plant Biology, 66(1), 297-327. https://doi.org/10.1146/annurev-arplant-050213-035923

Sato, M., Kakui, Y., & Toya, M. (2021). Tell the difference between mitosis and meiosis: Interplay between chromosomes, cytoskeleton, and cell cycle regulation. Frontiers in Cell and Developmental Biology, 9, 660322-660322. https://doi.org/10.3389/fcell.2021.660322