Meiosis
Tekst Storyboardowy
- Meiosis is the process by which one cell divides twice to produce four cells with just half as much genetic material as the original cell. Sex cells, or eggs in females and sperm in males, are these newly produced cells
- Meiosis is separated into nine stages. These are divided between the first and second times the cell divides (meiosis I and II).
- In Meiosis I, the first stage is Interphase, DNA in the cell is copied resulting in two identical full sets of chromosomes.Second stage is Prophase I,where the copied chromosomes condense into X-shaped structures that can be easily seen under a microscope.
- Third stage is Metaphase I, here the chromosome pairs line up next to each other along the centre (equator) of the cell. Next stage is Anaphase I, the pair of chromosomes are then pulled apart by the meiotic spindle, which pulls one chromosome to one pole of the cell and the other chromosome to the opposite pole.The last stage for meiosis I, Telophase I and cytokinesis in this stage the chromosomes complete their move to the opposite poles of the cell.
- During Meiosis II, Prophase II happens, now there are two daughter cells, each with 23 chromosomes (23 pairs of chromatids). Next stage is Metaphase II, In each of the two daughter cells the chromosomes (pair of sister chromatids) line up end-to-end along the equator of the cell.
- The third stage here in meiosis II is Anaphase II, where the sister chromatids are then pulled to opposite poles due to the action of the meiotic spindle. And finally the last stage, Telophase II and cytokinesis the chromosomes complete their move to the opposite poles of the cell
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