What are the stages of Meiosis?

Answer 1

First off, what crazydrummer347 has said is true in the exact opposite case. STAGES OF MEIOSIS: 1) MEIOSIS 1: i) Karyokinesis 1: *Prophase 1 *Metaphase 1 *Anaphase 1 *Telophase 1 ii) Cytokinesis 1 2) MEIOSIS 2: i) Karyokinesis 2: *Prophase 2 *Metaphase 2 *Anaphase 2 *Telophase 2 ii) Cytokinesis 2 ================================ STAGES OF MITOSIS: *Prophase *Metaphase *Anaphase *Telophase

Answer 2

Meiosis is the type of cell division by which germ cells (eggs and sperm) are produced. Meiosis involves a reduction in the amount of genetic material.

Meiosis comprises two successive nuclear divisions with only one round of DNA replication.
Four stages can be described for each nuclear division.

Interphase: Before meiosis begins, genetic material is duplicated.
First division of meiosis
Prophase 1: Duplicated chromatin condenses. Each chromosome consists of two, closely associated sister chromatids. Crossing-over can occur during the latter part of this stage.
Metaphase 1: Homologous chromosomes align at the equatorial plate.
Anaphase 1: Homologous pairs separate with sister chromatids remaining together.
Telophase 1: Two daughter cells are formed with each daughter containing only one chromosome of the homologous pair.

Second division of meiosis: Gamete formation
Prophase 2: DNA does not replicate.
Metaphase 2: Chromosomes align at the equatorial plate.
Anaphase 2: Centromeres divide and sister chromatids migrate separately to each pole.
Telophase 2: Cell division is complete. Four haploid daughter cells are obtained.
One parent cell produces four daughter cells. Daughter cells have half the number of chromosomes found in the original parent cell and with crossing over, are genetically different.

Meiosis differs from mitosis primarily because there are two cell divisions in meiosis, resulting in cells with a haploid number of chromosomes.

Answer 3

Before a dividing cell enters mitosis, it undergoes a period of growth called interphase. Some 90 percent of a cell's time in the normal cellular cycle may be spent in interphase.
G1 phase: The period prior to the synthesis of DNA. In this phase, the cell increases in mass in preparation for cell division. Note that the G in G1 represents gap and the 1 represents first, so the G1 phase is the first gap phase.

S phase: The period during which DNA is synthesized.
In most cells, there is a narrow window of time during which DNA is synthesized. Note that the S represents synthesis.

G2 phase: The period after DNA synthesis has occurred but prior to the start of prophase. The cell synthesizes proteins and continues to increase in size. Note that the G in G2 represents gap and the 2 represents second, so the G2 phase is the second gap phase.

In the latter part of interphase, the cell still has nucleoli present.

The nucleus is bounded by a nuclear envelope and the cell's chromosomes have duplicated but are in the form of chromatin.

In animal cells, two pair of centrioles formed from the replication of one pair are located outside of the nucleus.

Answer 4

Meiosis:

Meiosis (from the Greek word meion = reduce) comes after the G2-phase, when DNA replication (in the S-phase) is already concluded. Then DNA is still uncoiled. Two different divisions are distinguished within meiosis, i.e. meisis I (the true reductive division) and meiosis II.

Before a dividing cell enters meiosis, it undergoes a period of growth called interphase.

Interphase:
•G1 phase: The period prior to the synthesis of DNA. In this phase, the cell increases in mass in preparation for cell division. Note that the G in G1 represents gap and the 1 represents first, so the G1 phase is the first gap phase.
•S phase: The period during which DNA is synthesized. In most cells, there is a narrow window of time during which DNA is synthesized.
•Note that the S represents synthesis.
•G2 phase: The period after DNA synthesis has occurred but prior to the start of prophase. The cell synthesizes proteins and continues to increase in size. Note that the G in G2 represents gap and the 2 represents second, so the G2 phase is the second gap phase.
•In the latter part of interphase, the cell still has nucleoli present.
•The nucleus is bounded by a nuclear envelope and the cell's chromosomes have duplicated but are in the form of chromatin.
•In animal cells, two pair of centrioles formed from the replication of one pair are located outside of the nucleus.

Meiosis (summarizing)

During the two-step meiotic division not only the number of chromosomes and thus DNA amount are reduced, but DNA is exchanged between the homolog chromosomes of the original diploid cell (crossing-over and recombination). Four haploid daughter cells are formed through the meiotic process, each of them with an own genetical composition, different as well from that of the diploid mothercell, leading to genetic variation. Haploid reproduction cells are the product of meiotic division and a post-meiotic differentiation phase. In animals these cells are directly formed by differentiation (maturation) of the meiotic products. In plants meiotic products progress through mitotic division to meiospores that can further develop to become reproductive cells.

Meiotic stages: meiosis I and meiosis II

Meiosis I

The first division, also called reductional division, begins with the condensation of the chromosomes , followed by pairing and exchange of DNA between homologe chromosomes ; crossing-over). The the homologe chromosome pairs (bivalents separate and move to two opposite domains of the cell .

Characteristics of the stages of meiosis I

Prophase I: (Gr. pro = before) DNA condensates and crossing-over (exchange of genetic material) occurs between twisted homolog chromosomes. Prophase I is divided into
Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis

Metaphase I (Gr meta= middle): The homolog chromosomes (bivalents) are paired in the equatorial plane. The chromatides are strongly condensed. Bivalents are positioned in such a way that homolog centromeres lay at either side of the equatorial plane. Only chiasmata (crossings) hold the bivalents of homolog chromosomes together.

Anaphase I (Gr ana = apart) begins when the chromosomes are pulled to the opposite poles in the cell. The units of a homolog pair move apart (separation of bivalents) in opposite direction; however, the chromatides of each chromosomes stay joined.

Telophase I (Gr telos = end): The chromosomes have reached the poles and decondense, while a new nuclear envelop is formed.

Meiosis II

In this second round of division, also called equatoriale division, the two chromatides of each chromosome separate . The sister chromatides move to opposite poles and cytokinesis leads to the formation of four meiotic products .

Characteristics of the stages of meiosis II

Prophase II : typical for this stage is the presence of a haploid number of chromosomes that condense again. The two sister chromatides of a chromosome are still coupled together at the centromere.

Metaphase II: The chromosomes move again to the equatorial plane between the poles. However, this plane is oriented perpendicularly with respect to the previous one of meiosis I.

Anaphase II: The centromeres separate and the sister chromatides are pulled apart to opposite poles by the spindle.

Telophase II: The former sister chromatides have reached the poles. A nuclear envelop is formed around each nucleus, while chromosome despiralize again.

Answer 5

The following links will be useful to you

http://biology.about.com/od/meiosis/ss/meiosisstep.htm

http://taggart.glg.msu.edu/bs110/meiosis.htm

Answer 6

Please vist :

http://www.vcbio.science.ru.nl/en/virtuallessons/meiostage/