Cell Division : Mitosis and Meiosis

Within this week's lesson, I have familiarized the concepts of how mitosis and meiosis work and how do they differ not only in terms of process. For me, it is really obvious that mitosis is really very easy comparing with meiosis but also is easy to understand with much more stages. And always remember that the interphase is always first before the cellular division begins having the substages of G1, G2, and S(synthesis).

Mitosis is always known as the body cell itself which produces asexually. Skin cells, muscular cells, blood cells, and gastrointestinal cells, and brain cells are good examples of demonstrating mitosis only producing by themselves. Take note that mitosis is always cyclic meaning that it can repeat the process all over again when needed by other organs from different parts of the body. Without mitosis, we would have been dead or even get memory gaps in an instant. Because all parts of the body need cells not only because they're the basic unit of life but they also play important role. That is to replace all types of cells needed whenever an cut is located, or they can even replace brain cells making you remember everything you have learned.

Mitosis has the following basic processes :

1. Prophase - the initial stage of mitosis having a nuclear membrane and centrioles ; and has the following substages namely leptotene(coiling of chromosomes), zygotene(beginning of having synapsis), pachytene(completion of synapsis), diplotene(uncoiling/overlapping of chromosomes), and diakinesis(shortening of chromosomes).
a. Early Prophase - centrioles form ; nuclear membrane starts to disintegrate ; chromosomes start to thicken having "x" shapes
b. Late Prophase - centrioles start to move apart ; nuclear member breaks up ; chromosomes became much thicker
2. Metaphase - chromosomes align in the middle ; spindle fibers formed pulling the chromosomes apart
3. Anaphase - as the chromosomes are pulled apart half of it are pulled toward the opposite poles and the other half at the other pole
4. Telophase - cleavage start to form ; two nuclei start to form ; chromosomes become indistinct ; daughter cells are formed called cytokinesis


Meiosis is one of the most important lesson required to master if tackling the reproductive system. This is because meiosis occurs/involves in the gametes known as sexual organs. The significant difference between meiosis and mitosis have is that the haploid and the diploid number of chromosomes will change having 23c or haploid (x).

Here are the following stages of meiosis :

First Meiotic Division
1. Prophase I - follows the substages of the following in order : leptotene, zygotene, pachytene, diplotene, and diakinesis
2. Metaphase I - similar with the metaphase stage in mitosis but its maternal chromosomes are formed on the other side of the equator.
3. Anaphase I - also similar with the anaphase stage in mitosis but paired chromosomes move toward the opposite poles held by centromeres
4. Telophase I - cleavage starts to form like in the telophase stage in mitosis

Second Meiotic Division
1. Prophase II - spindle fibers from the centrioles to the opposite poles in different positions
2. Metaphase II - mitotic spindle fibers are set up ; chromosomes line up along the equatorial line
3. Anaphase II - centromere divides ; sister chromatids separate to the opposite poles
4. Telophase II - cleavage forms again ; a diploid gamete always has four haploid daughter cells