2 of 6

Write now Article Tools

Cells divide in order to replace worn out or old cells, and to create reproductive cells, or gametes. Mitosis is the division of non-sex cells, or somatic cells. Meiosis is the process by which a parent cell can make gametes, or sex cells. In mitosis, a parent cell makes two identical daughter cells, which are called diploid (2n) cells because they have two copies of each chromosome. In meiosis, parent cells divide to make gametes that are haploid (n), with only one copy of each chromosome. Haploid gametes will unite in fertilization to make a diploid zygote which has the potential to become a new organism.

HUMAN CHROMOSOME NUMBER EXAMPLE
For example, in humans all somatic cells have 46 chromosomes, pairs of each of the 23 unique kinds of chromosomes. One set of the 23 chromosomes came from mom's gamete and one set came from dad's gamete. They united in fertilization to make the 46 pairs in the original zygotic cell that divided to give rise to the individual. In the individual's body, all the somatic cells go through mitosis to make diploid somatic cells, such as liver cells, kidney cells, and skin cells. A small group of parent cells go through meiosis instead, to make haploid gametes for future reproduction.

Including Interphase and Cytokinesis, there are 6 stages in the mitotic cell cycle. In order, the three major portions are Interphase, Mitosis, and Cytokinesis, and Mitosis consists of 4 separate steps.

INTERPHASE
Interphase means "between phases" and is literally the stage between division of the cell and nucleus. Interphase is largely a time of cellular growth and development, where the cell performs its normal functions such as protein synthesis, photosynthesis, and cellular respiration, may increase in size, and gets itself ready to go through mitosis and cytokinesis. Interphase has 3 portions to it - G1, or Gap 1, where the cell largely concerns itself with growing, S which refers to Synthesis, where the cell duplicates its genetic material, and G2 or Gap 2, where the cell checks to see if it is ready to move onto Mitosis.

MITOSIS - PROPHASE
Mitosis begins with Prophase, or "first phase." Prophase is when the nuclear membrane around the genetic material dissolves. The genetic material, or DNA, condenses from stringy chromatin into shorter, more compact chromosomes. These are X-shaped in this stage because the two identical copies from the S part of Interphase remain attached for now. The point at which they are attached is known as the Centromere. In prophase,

• 1
• 2
• next page >>

Add your voice

Know something about The stages of a mitotic cell cycle?
We want to hear your view. Write now!