Translations:Adventist Youth Honors Answer Book/Health and Science/Heredity/46/en

Meiosis I

This is the process by which a diploid cell divides into two haploid cells. These two haploid cells still have duplicated chromosomes, however, so the two cells must enter Meiosis II following.

Prophase I

During Prophase I, the chromosomes cross over and the centrioles move to opposite ends of the cell and begin to form the mitotic spindle.

Metaphase I

The chromosomes line up on the metaphase plate, and the microtubules from each centriole grab one chromosome from each homologous pair.

Anaphase I

The microtubules pull the chromosome pairs apart, so that each centriole gets one chromosome from each pair.

Telophase I

The cell membrane constricts in order to cut off the two cells, and nuclei begin to form around the chromosomes. The chromosomes are still duplicated, so now the cells undergo Meiosis II.

Meiosis II

This is the process by which the two haploid cells (with duplicated chromosomes; produced during Meiosis I) split into two more cells, so that the final product of Meiosis is four haploid cells.

Prophase II

The centrioles duplicate again and move to opposite ends of the cells, and the spindles begin to form.

Metaphase II

The chromosomes line up on the metaphase plate and the spindles from the centrioles attach to each chromosome.

Anaphase II

The centrioles pull the chromosomes apart, much like in mitosis, and each centriole gets one half of each chromosome.

Telophase II

The cell membranes constrict and a nuclear membrane forms around the chromosomes. The end result of meiosis is four cells with only one chromosome from each homologous pair. These are called gametes.