Meiosis is the process by which a cell divides in preparation for sexual reproduction.
Meiosis has 2 phases - Meiosis I and Meiosis II. Both are similar to mitosis, the process of a cell dividing for asexual reproduction.In Meiosis I, there are 5 sub-phases: Prophase I, Metaphase I, Anaphase I, Telophase I, and Cytokinesis.
Here's a quick overview of each sub-phase:
MEIOSIS I
· Prophase I: Chromosomes form from the DNA in the nucleus and the nuclear membrane dissolves, letting the chromosomes into the cytoplasm. This is when crossing-over occurs.
Metaphase I: Spindle fibers attach to the chromosomes and the homologous chromosomes pair up in the center of the cell.
· Anaphase I: Spindle fibers begin to shrink and pull the pairs apart, towards the opposite poles of the cell.
·Telophase I: The spindles break down and nuclear membranes form around each of the two groups of chromosomes.
·Cytokinesis: The cell divides in the middle, splitting the cytoplasm and forming two new cells. These cells each have a full set of chromosomes.
MEIOSIS II
·Prophase II: The nuclear membrane of each of the two cells formed in Meiosis I break down.
·Metaphase II: Spindle fibers form and line up the sister chromatids in the middle of each cell.
·Anaphase II: Spindle fibers begin to shrink and pull sister chromatids apart, towards the opposite poled of the cell.
·Telophase II: The spindles break down and new nuclear membranes form.
·Cytokinesis: The cytoplasm splits and two new cells are formed. These cells are haploid, meaning they only have half a set of chromosomes.
Whew. Hope that helps! :)
