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Can anyone put meiosis (A level) into the simplest format possible please?!

LiviB

Bio exam tomorrow and it's something I thought I knew but apparently not! Thank you xxx

Reply 1

Anoncauterize

Original post by LiviB

Bio exam tomorrow and it's something I thought I knew but apparently not! Thank you xxx

Meiosis is the division of cells from germ cells to from sex cells (games) in animals. It has the same phases as mitosis, (Interphase) then prophase, metaphase, anaphase telophase and then cytokinesis, then undergoes a second phase.

It produces 4 haploid daughter cells from 1 diploid mother cell. It consists of a phase one and phase two, with genetic material doubling during interphase before hand.

In Prophase 1, chromosomes condense and become visable and two sister chromatids joined to a centromere can be seen, in metaphase 1 they line up along the equator in pairs, are separated apart in anaphase 1 too the pols by spindle fibres, where the nuclear envelope reforms in telophase 1, where division finally occurs in cytokenisis. (Very General sorry). They then undergo the second phase, the same general thing happens apart from crossing over, and the sister chromatids are pulled apart from the centromere in anaphase 2 by the spindle fibres, telophase 2 and cytokinesis 2 then occour to leave 4 haploid cells.

You must remember that in prophase 1 there is crossing over of sister chromatids which causes variation, important in reproduction, and in anaphase 1 and 2 independent assortment of homologous pairs, in anaphase when the spindle fibres pull the pairs (A1) and the sister chromatids (A2) apart at the equator to the poles of the cell. It is random which chromosome will be assorted to either pole and therefore many genetically diffenet gamets can be formed.

Look at the text book to check as I may have made a mistake somewhere, and also the differences between animal and plant cell meiosis may be asked.

I have it tomorrow as well so good luck

(edited 5 years ago)

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