What is Mitosis:
Mitosis is the cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.
The 5 Stages of Mitosis:
Interphase:
This is the longest phase of the cell cycle, known as the resting phase. The cell does not divide, and it's the period of cell growth and metabolism. The DNA replicates or duplicates in this phase.
Prophase:
This is where the chromosomes become visible in the center of cell and the centrioles separate and begin forming a spindle fiber apparatus.
Metaphase:
In this phase the centrioles are opposite poles, replicated chromosomes line up at equator & spindle fibers attach to centromeres that hold chromatids together.
Anaphase:
This is the shortest phase of Mitosis. Its where the duplicated centromeres of each pair of sister chromatids separate, and the now-daughter chromosomes begin moving toward opposite poles of the cell due to the action of the spindle.
Telophase:
This phase is where the chromosomes reach opposite poles of cell, reversal of many prophase events occurs, chromosomes uncoil & become thread like chromatin & a nuclear elope forms around chromosomes. Plus Cytokinesis occurs.
What is the cell cycle?
Interphase:
- the period of cell growth and metabolism
Prophase:
- chromosomes become visible in the center of cell and the centrioles separate and begin forming a spindle fiber apparatus.
Metaphase:
- chromosomes line up at equator & spindle fibers attach to centromeres that hold chromatids together.
Anaphase:
- duplicated centromeres of each pair of sister chromatids separate, and the now-daughter chromosomes begin moving toward opposite poles of the cell due to the action of the spindle.
Telophase:
- chromosomes reach opposite poles of cell, reversal of many prophase events occurs, chromosomes uncoil & become thread like chromatin & a nuclear elope forms around chromosomes
- the period of cell growth and metabolism
Prophase:
- chromosomes become visible in the center of cell and the centrioles separate and begin forming a spindle fiber apparatus.
Metaphase:
- chromosomes line up at equator & spindle fibers attach to centromeres that hold chromatids together.
Anaphase:
- duplicated centromeres of each pair of sister chromatids separate, and the now-daughter chromosomes begin moving toward opposite poles of the cell due to the action of the spindle.
Telophase:
- chromosomes reach opposite poles of cell, reversal of many prophase events occurs, chromosomes uncoil & become thread like chromatin & a nuclear elope forms around chromosomes
What are the stages of meiosis?
Prophase:
1. Just like in mitosis, during prophase, DNA condensation occurs, the nuclear envelope and nucleoli disappear, and the spindle starts to form. The big difference is what is going on with the chromosomes themselves. As DNA condensation proceeds and the chromosomes first become visible, they are visible as tetrads. So, tetrads become visible during prophase.
2. Chromosomes with two chromatids become visible as they condense
Metaphase:
1. Tetrads line up at the equator. The spindle has completely formed. It is during prophase I and metaphase I that genetic recombination is occurring. Take a look at the genetic recombination page to find out about how that happens here. Keep in mind that it only happens when there are tetrads, so as soon as anaphase I gets going, genetic recombination is over.
2. Chromosomes with two chromatids line up at the equator. The spindle is fully formed.
Anaphase:
1. Tetrads pull apart and chromosomes with two chromatids move toward the poles.
2. Chromosomes split, so that a chromosome with only one chromatid heads toward each pole.
Telophase:
1. Chromosomes with two chromatids decondense and a nuclear envelope reforms around them. Each nucleus is now haploid. Keep in mind that it is not the number of chromatids per chromosome that determine whether a cell is diploid or haploid, but, it is the number of chromosomes and whether they are paired that determines this.
2. Chromosomes with only one chromatid decondense and get surrounded by new nuclear envelopes. The four daughter cells are now all haploid and have the right amount of DNA. They are ready to develop into sperm or eggs now.
1. Just like in mitosis, during prophase, DNA condensation occurs, the nuclear envelope and nucleoli disappear, and the spindle starts to form. The big difference is what is going on with the chromosomes themselves. As DNA condensation proceeds and the chromosomes first become visible, they are visible as tetrads. So, tetrads become visible during prophase.
2. Chromosomes with two chromatids become visible as they condense
Metaphase:
1. Tetrads line up at the equator. The spindle has completely formed. It is during prophase I and metaphase I that genetic recombination is occurring. Take a look at the genetic recombination page to find out about how that happens here. Keep in mind that it only happens when there are tetrads, so as soon as anaphase I gets going, genetic recombination is over.
2. Chromosomes with two chromatids line up at the equator. The spindle is fully formed.
Anaphase:
1. Tetrads pull apart and chromosomes with two chromatids move toward the poles.
2. Chromosomes split, so that a chromosome with only one chromatid heads toward each pole.
Telophase:
1. Chromosomes with two chromatids decondense and a nuclear envelope reforms around them. Each nucleus is now haploid. Keep in mind that it is not the number of chromatids per chromosome that determine whether a cell is diploid or haploid, but, it is the number of chromosomes and whether they are paired that determines this.
2. Chromosomes with only one chromatid decondense and get surrounded by new nuclear envelopes. The four daughter cells are now all haploid and have the right amount of DNA. They are ready to develop into sperm or eggs now.
Extra Research:
How is Mitosis affected by cancer?
Without the process of mitosis there would be no cancer. Cancerous cells ignore or override some of the control measures of this type of cell division. Cancer and mitosis are closely related. Mitosis is the process by which cells reproduce, and without it cancerous cells wouldn't be able to form tumors and spread through the body. Cancer starts in the body's cells. All of our organs and tissues are made up of cells. Each cell contains genes that determine how the cell grows, functions, and eventually dies.Mitosis is the most common form of cell division and it's where once cell becomes two. It is necessary because:
1) cells wear out, die and need to be replaced
2) new cells are needed to repair damaged tissues
3) they allow a body to grow. It is mitosis that makes it possible for new skin tissue, bone tissue and muscle tissue to be made, and the only source material is other cells.
1) cells wear out, die and need to be replaced
2) new cells are needed to repair damaged tissues
3) they allow a body to grow. It is mitosis that makes it possible for new skin tissue, bone tissue and muscle tissue to be made, and the only source material is other cells.
References:
http://en.wikipedia.org/wiki/Mitosis#Interphase
https://au.answers.yahoo.com/question/index?qid=1006031905251
http://www.cellsalive.com/mitosis.htm
http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells3.html
http://cyberbridge.mcb.harvard.edu/mitosis_4.html
http://www.biology4kids.com/files/cell2_mitosis.html
http://www.vcbio.science.ru.nl/en/virtuallessons/mitostage/
http://www.brighthub.com/science/genetics/articles/27812.aspx
http://www.brighthub.com/science/genetics/articles/33788.aspx
http://faculty.stcc.edu/BIOL102/Lectures/lesson9/stepbystep.htm
https://au.answers.yahoo.com/question/index?qid=1006031905251
http://www.cellsalive.com/mitosis.htm
http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells3.html
http://cyberbridge.mcb.harvard.edu/mitosis_4.html
http://www.biology4kids.com/files/cell2_mitosis.html
http://www.vcbio.science.ru.nl/en/virtuallessons/mitostage/
http://www.brighthub.com/science/genetics/articles/27812.aspx
http://www.brighthub.com/science/genetics/articles/33788.aspx
http://faculty.stcc.edu/BIOL102/Lectures/lesson9/stepbystep.htm