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1 Meiosis
Meiosis is the process by which sex cells (gametes cells) are produced. These cells have only 23 chromasomes (compared to somatic cell's 23 pairs), and they contain a variety of mechanisms for genetic variation.
Meiosis happens in two phases, which happens each in 4 phases:
1.1 Meiosis 1
The purpose of meiosis 1 is to take the 23 pairs of 2-chromatid chomasomes in germline cells (2n diploid, contains two sets of homologous chromosomes) and mix them to separate into two cells containing 23 singular 2-chromatid chromasomes (1n haploid, contains only one set of genes).
- (P)rophase 1: the starting cell, a diploid, dissolves its nucleaus and genetic information flows out. Also, KBhBIO101GeneticVariation by crossing over and independent assortment happens.
- (M)etaphase 1: homogous PAIRS of chromosomes (note! pairs!!! not the chromasomes) line up along the metaphase plate, forming a double-filed lines
- (A)naphase 1: seperate the homologous pairs to the opposite ends of the cell
- (T)elophase 1: the two new half-cells proceed to seperate further, creating new nuclear envelopes enveloping the 23-unpaired sister chromatids
Figure 1: Pasted image 20210426220455.png
1.2 Meiosis 2
The 23 2-chromatid Chromasomes becomes seperated into two more cells each with 23 1-chromatids. This is more similar to a good-ol KBhBIO101Mitosis.
- (P)rophase 2: new spindles form, again! and the new haploids' nuclear envelope will start dissoving
- (M)etaphase 2: the sister chromatids (chromasomes) align themselves along the metaphase plate, attaching themselves to the spindles
- (A)naphase 2: spindles pull the sister chromatids away from each other
- (T)elophase 2: new nuclear envelope forms and the chromasomes dissolves