#10 & # 11 COMPARE & COMTRAST MITOSIS & BINARY FISSION &MEISOSIS

#10-Mitosis is the process of forming identical daughter cells by replicating and dividing the original chromosomes, in effect making a cellular xerox. Commonly the two processes of cell division are confused. Mitosis deals only with the segregation of the chromosomes and organelles into daughter cells.
Click here to view an animated GIF of mitosis from http://www.biology.uc.edu/vgenetic/mitosis/mitosis.htm

Prokaryotes are much simpler in their organization than are eukaryotes. There are a great many more organelles in eukaryotes, also more chromosomes. The usual method of prokaryote cell division is termed BINARY FISSION. The prokaryotic chromosome is a single DNA molecule that first replicates, then attaches each copy to a different part of the cell membrane. When the cell begins to pull apart, the replicate and original chromosomes are separated. Following cell splitting there are then two cells of identical genetic composition (except for the rare chance of a spontaneous mutation).

Mitosis is the division of the nucleus into two daughter nuclei. Binary fission is the dividing of a cell into two cells. Either a prokaryotic or eukaryotic cell can do it.


Binary fission is asexual reproduction for prokaryotes whereby a cell duplicates its chromosomes and then splits into two identical cells (each with one copy). Mitosis is essentially the same thing for eukaryotes except that there is an extra step because the nucleus needs to divide too. Mitosis is just the division (essentially, binary fission) of a cell's nucleus
http://www.cellsalive.com/mitosis.htm

#11 AND MEIOSIS

Meiosis produces daughter cells that have one half the number of chromosomes as the parent cell.

2N ® N

Meiosis enables organisms to reproduce sexually. Gametes (sperm and eggs) are haploid.
Meiosis involves two divisions producing a total of four daughter cells.
Click here to go to the chapter on meiosis.

Summary of the Phases of Meiosis

A cell undergoing meiosis will divide two times; the first division is meiosis 1 and the second is meiosis 2. The phases have the same names as those of mitosis. A number indicates the division number (1st or 2nd):

meiosis 1: prophase 1, metaphase 1, anaphase 1, and telophase 1
meiosis 2: prophase 2, metaphase 2, anaphase 2, and telophase 2

In the first meiotic division, the number of cells is doubled but the number of chromosomes is not. This results in 1/2 as many chromosomes per cell.
The second meiotic division is like mitosis; the number of chromosomes does not get reduced.

Both Meiosis and Mitosis are found in complex organisms which reproduce sexually. Mitosis may be used for human growth, the replenishment of depleted organs and tissues, healing, and sustenance of the body. Identical versions of cells can be created to form tissues through Mitosis. Meiosis is a special process reserved for the creation of the egg and sperm cells. The same patterns may be found in many species of plant and animal cell reproduction.

Significance of Mitosis vs. Meiosis

The importance of mitosis is the maintenance of the chromosomal set; each cell formed receives chromosomes that are alike in composition and equal in number to the chromosomes of the parent cell.

Occurrence

Meiosis is found to occur in humans, animals and plants while mitosis is found in single-cell species as well.

Mitosis vs. Meiosis: Process Differences

Mitosis is a method of reproduction for single celled organisms that reproduce asexually. An identical version of the organism is created through splitting of the cell in two. Meiosis may result in millions of spermazoa and egg cells with unique genetic patterns. The mating of the two cells formed by meiosis results in a unique genetic offspring of the same species. Meiosis is a major factor in evolution, natural selection, and biodiversity. The processes of cellular division shown in mitosis and meiosis are present in all manner of life forms including humans, animals, plants, fungi, and single celled organisms and species. Essentially any cell based organism of which all organic life is based will exhibit some form of mitosis and meiosis for growth and reproduction of the individual and species.