(before chromosome replication)
Tetrad formed by
Tetrads align randomly
at the metaphase plate
separate but sister chromatids
remain together during anaphase I
No further chromosomal
replication; sister chromatids
separate during anaphase II
One, consisting of prophase, metaphase,
anaphase, and telophase.
in the body
Two, each consisting of prophase, metaphase, anaphase, and telophase.
DNA replication does not occur between the two nuclear divisions.
Does not occur.
Occurs during prophase I; tetrads form, allowing crossovers.
Two. Each diploid (2
) cell is identical to
the mother cell.
Four. Each haploid (
) cell contains half as many chromosomes as the
mother cell and is genetically different from the mother cell.
For development of multicellular adult from
zygote. Produces cells for growth and tissue
repair as multicellular adult develops. Ensures
genetic makeup of all body cells is constant.
Produces cells for reproduction (gametes). Introduces genetic variability
in the gametes and reduces chromosomal number by half so that when
fertilization occurs, the normal diploid chromosomal number is restored
(in humans, 2
Daughter cells of meiosis II
of Meiosis I
align at the
Sister chromatids separate
Comparison of mitosis and meiosis in a mother cell with a diploid
) of 4.
(Not all the phases of mitosis and meiosis are shown, and only one possible
alignment of the tetrads at metaphase I is illustrated.)