Mitosis & Meiosis

Maddie Hopkins // January 13, 2014

MITOSIS

The main purpose of mitosis is to produce cells of the body to aid in growth and repair. There are four phases of mitosis; prophase, metaphase, anaphase, and telophase.






The Phases of Mitosis

Prophase; the first and longest phase of mitosis. During prophase, chromosomes become visible, centrioles seperate, and a spindle starts to form all while the nuclear envelope of the cell breaks down.


Metaphase; the second phase of mitosis. During this phase the chromosomes line up down the center of the cell. Every chromosome connects to a spindle fiber.


Anaphase; the third phase of mitosis. During anaphase, chromosome seperate from each other until they are in two completely different groups at each end of the cell. This phase usually ends when the chromosomes stop moving.


Telophase; the fourth phase of mitosis. During this last phase, while the chromosomes are at opposite ends of the cell from going through anaphase, two new nuclear envelopes start to form.



Cytokinesis

Cytokinesis is not a phase of mitosis but the process of cell division is not complete without this. The point of cytokinesis is to divide the cytoplasm and usually occurs about the same time as telophase.


mitosis

MEIOSIS

Meiosis is a process of cell division necessary for sexual reproduction to produce sex cells, commonly known as gametes. During meiosis, the number of chromosomes in a cell are cut in half and result in 4 haploid cells that genetically differ from each other and the original parent cell.


{below is a picture depicting the process of meiosis}

Meiosis

Crossing Over

The process of crossing over occurs during meiosis when two homologous chromosomes pair up and exchange pieces of their genetic material.



Crossing over benefits genetics and is very important because it creates a variation of possible allele combinations in gametes, therefor creating a wide variety of genetic diversity.

To Summarize...

Mitosis is to help body cells grow and develop, whereas meiosis is to produce sex cells.


The process of mitosis follows the phase sequence of IPMAT (interphase, prophase, metaphase, anaphase, and telophase), whereas meiosis follows the sequence of IPMATPMAT (interphase, prophase, metaphase, anaphase, telophase, and then prophase, metaphase, anaphase, and telophase again).


Mitosis results in two identical diploid daughter cells, whereas meiosis begins with a diploid cell but results in four completely different haploid cells.