Mitosis versus Meiosis
Chromatin - this is just the material; you use the term "chromatin" when you're not talking about
individual molecules, but about all of the genetic material of a cell (usually in interphase)
Chromatid - chromatids don't have any independent existence; the term "chromatid" only refers to a
molecule of DNA that is joined at the centromere to another chromatid
Chomosomes - this is used in talking about independent molecules of DNA (they can be either one copy
or two copies joined together as two sister chromatids)
Tetrad - two chromosomes together, each of which consists of two sister chromatids
Mitosis
Prophase
Metaphase
Anaphase
Chromosomes
2n
2n
4n (2n in each daughter cell)
Telophase
4n
Chromatids
4n
4n
----- (we don’t call them chromatids
when they’re no longer attached)
-----
Meiosis
Prophase I
Metaphase I
Chromosomes
2n
2n
Chromatids
4n
4n
Anaphase I
2n
4n (chromatids do
not separate in
meiosis I)
4n
2n
2n
-----
Telophase I
Prophase II
Metaphase II
Anaphase II
2n
n
n
2n (n in each daughter
cell)
Telophase II
2n
----For meiosis II, we only look at one of the daughter cells from meiosis I.
Tetrads
----n (this is the
only time there
are tetrads)
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