I need to know the stages of meiosis and why it's important to know them.

Question

Why is it important to know these stages???

Answer 1

Meiosis is very similar to mitosis, with a few exceptions:

1- Mitosis can occur in all cells that ARE NOT a sex cell (like egg or sperm), whereas meiosis ocurs only in sex cells

2- Meiosis Produces four cells from 1 instead of 2 (like mitosis)

3- Meiosis produces HAPLOID cells instead of DIPLOID cells

4- During PROPHASE I of meiosis, a unique process occurs called crossing over occurs, where homologous chromosomes may exchange portions of their chromatids and produce unique NEW genetic arrangements.

The 4 differences above are WHY the steps of Meiosis ARE IMPORTANT. The process produces sex cells, which are haploid and may also produce NEW UNIQUE genetic combinations.  These unique arrangement are one of the mechanisms of evolution.

The stages are 

1-Prophase I

2- Metaphase I

3- Anaphase I

4- Telophase I

5- Prophase II

6- Metaphse II

7- Anaphase II and

8- Telophase II

Answer 2

Meiosis, very easy to confuse with Mitosis.  I have always had my students go to this excellent site to see what is happening: http://www.cellsalive.com/meiosis.htm.  This is an excellent animation. 

Remember that Meiosis is like Mitosis because it goes through all the stages (& in the same order) but it goes through interphase only once.  Now why that is important?

 

Answer 3

The best way to remember the stages of meiosis is probably to use a diagram. Here's a convenient one: http://upload.wikimedia.org/wikipedia/commons/5/54/Mei osis_diagram.jpg

The different stages are important because there are different processes occuring within each stage, and they correlate to each other. For example, whether you're talking about Telophase in Mitosis or Telophase I or Telophase II in meiosis, they refer to the same process, the forming of two separate neuclei in the cell and getting ready to split. Giving it a name helps people refer to the process without saying "that one thing that happens at this time" and being vague.

Answer 4

Stacy, Kathy and Oly wonderfully provided details on Meiosis and they didn't leave any meat on the bones form me. However I would like to speak about the WHY? regarding meiosis.

 

Meiosis provides for a large amount of genetic diversity that may allow for survival in starkly contrasting environments.

 

Reasons to learn Meiosis are many but I’ll give you two more, both making the study of meiosis critical. Contact the Turner Syndrome Society to visit local patients and the American Association for Klinefelter syndrome.

Burden to society: many of the aneuploidy conditions spontaneously abort however those zygotes that survive to adulthood require institutionalization usually paid for by Medicaid and or Medicare and at a time of dwindling resources, research for a cure is paramount to survival of state Medicaid and Federal Medicare services.

Burden to family: patients physically able to live at home will continue to require supervision, adaptive equipment (expensive), frequent outpatient clinic visits (expensive long-term medication) and hospitalization (Medicine and Surgery), (expensive).

Meiosis

Ø  Process of producing Gametes (Germ cells) and thus setting the stage for genetic diversity completed during sexual reproduction

Ø  Gametes: male (Sperm) and female (Ovum)

Ø  Number of chromosomes: Somatic cell [Diploid 46 (2n)] and Gametes [HAPLOID 23 (n)]

Ø  Fertilization: sperm (Haploid 23) + Ovum (Haploid 23)= Zygote [Diploid]

Ø  EUPLOID (n times 1 → ∞) state is an exact multiple of the Haploid (n) state. VERY IMPORTANT to your question.

Ø  What if the chromosome number is NOT Euploid? This is called ANEUPLOID (not a multiple of Haploid (n) state)

Ø  Examples of aneuploidy of Sex Chromosomes include: Turner Syndrome (45 X) and Klinefelter Syndrome (47 XXY). See web page UTMB Medical Genetics and Dysmorphology for additional information. http://www.utmb.edu/pedi_ed/CORE/MedicalGenetics/page_11.htm.

Ø  Turner’s patients have severe cardiac anomalies, gonadal dysgenesis (see impact on bones and costs) and have near normal intelligence but have impaired mathematics skills and visual spatial orientation

Ø  Numerical aberrations that result in Turner’s and Klinefelter (sex cell aneuploidy) are examples of the importance of learning phases of Meiosis.

Ø  If you have time read about polyploidy conditions; 1) Spontaneously aborted fetus’ 2) Tumors and 3) specific differentiated cells