Prophase II
Stages of Meiosis
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EUGENE M. MCCARTHY, PHD GENETICS
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| A human karyotype colored to show chromosome pairs (Full-size image) |
Prophase II
| Note: Meiosis II is very similar to mitosis, except that during meiosis II only one member of each chromosome homolog pair is present, whereas in mitosis both are (it will help you remember this if you pronounce mitosis — only in your own mind! — as "my-TWO-sis"). |
Prophase II, the first step of meiosis II, begins with the two daughter cells produced by the first meiotic division (see figure right). As in prophase I, the chromosomes are condensed. During this stage of spermatogenesis, the cells are called secondary spermatocytes, or during oogenesis, secondary oocytes.
If there was an interkinesis, then the nuclear envelopes begin to break down again during this stage. The centrosomes have replicated and are moving toward the poles.
Again, the chromosomes are not yet attached to the spindle apparatus, which is growing outward from the centrosomes.
A common question: What comes after prophase? Answer: Metaphase!
Etymology:
The name prophase is derived from the Latin word pro, meaning before. Some other bio-terms starting with pro: prognosis, prokaryote, pronucleus.