Question

1. For meiosis, describe the major differences between metaphase I and metaphase II?

2. How is anaphase I in meiosis different than anaphase in mitosis?

3. Explain how meiosis II is more like mitosis than meiosis one is.

4. Define a tetrad of chromosomes.

5. In what ways are homologous chromosomes similar to each other and different than each other?

Please answer all question in full typed

Answer 1

1) Difference between metaphase 1 and metaphase 2 :
In metaphase 1 tetrads are arranged at metaphase equator while in metaphase 2 single chromosome are arranged at the metaphase equator.
In metaphase I :Microtubules of one pole are attached to kinetochore of one of the two chromosome facing the same pole while in metaphase 2 microtubules are attached to the kinetochores of the centromere on either side of single chromosome.
In metaphase 1 Single chromosome moves towards the opposing poes at anaphase 1 whie in metaphase 2 one pair of sister chromatids move towards the opposing poles at anaphase 2.
In metaphase 1 the metaphasic plate is arranged in equidistant to the opposing poles while in metaphase 2 the metaphasic plate rotates at 90 degrees compared to metaphase 1.

2)Anaphase of mitosis :
Anaphase is the stage during which the centromere splits and the chromatids separate. The chromososme moves apart towards the opposite poles . The chromosomes are genetically identical.
Anphase ! of meiosis :
The homologous chromosome separate ,while the chromatids remain attached at their centromeres .Hence in anaphase 1 the chromosomes of each bivalent pair separates,while sister chromatids remain together.
The clevage of centromere takes pllace in anaphase of mitosis but it doesn't occur in anaphase of meiosis.

3) Meiosis 2 is similar to mitosis because chromosomes are duplicated, it separates the chromososme to have sister chromatids in each cell.
In both the process chromososme is separated and 1 cell gives rise to two other. (In meiosis we get 4 out of 2 cells)
Whereas Meiosis 1 and 2 differ because in Meiosis 1 , it reduces the chromosome number in the daughter cell and in meiosis 2 , equalises the chromosome number of both parent and daughter.

4) Tetrad is a four part structure that forms during the prophase of meiosis and consists of two homologous chromosomes , each composed of two sister chromatids .
It can also be called as foursome of chromatids that forms when replicated homologous chromosomes align.

5)One chromosome of each homologous pair comes from mother and one comes from father.
They are similar because each carries same genes in same order.
They are different because alleles for each trait may differ in homologous chromosome, they have different version of same genes.