Study Guide to The Stages of Meiosis

Stage

Developments

Interphase

Prophase I

The DNA is tightly coiled into chromosomes (these are visible) Nuclear envelope disappears

(This occurs before birth in female gametes, and than meiosis stops).

Metaphase I

The lining up of the tetrads (the combination of both chromosomes line up along the midline.

The centrioles line up at opposite poles and the spindles begin to attach to the centromeres of the chromosomes

(In females meiosis starts again for one primary oocyte each month starting at puberty)

Anaphase I

The centromeres do not break.

The homologous chromosomes (and the crossover material) move to separate poles, but they may attach to the sister chromatids.

So each daughter cell will only have one of each pair of chromosomes

Prophase II

This involves both daughter cells.

The DNA is tightly coiled into chromosomes (these are visible) and the sister chromatids are still attached by the centromere.

Nuclear envelope disappears

"Proceed again"

Metaphase II

The lining up of the chromosomes along the midline in both daughter cells.

The centrioles line up at opposite poles and the spindles begin to attach to the centromeres of the chromosomes

In the "middle"

again

Anaphase II

The centromeres break.

The sister chromatids move to the opposite poles.

"And away

we go"

again

The chromosomes reach the opposite poles and the nuclear envelope begins to reform around each of the groups of chromosomes and cytokinesis occurs.

The end product is 4 haploid cells.

Male: 4 sperms cells or

Female: 3 polar bodies and one oocyte (cytokinesis does not occur evenly and all of the cytoplasm remains with the oocyte to nurture the developing embryo.