Self Assessment Answer # 2 for Lesson 5 by Dr Jamie Love 2002 - 2005

All the chromosomes in meiosis I develop only one kinetochore each. (In mitosis each chromosome develops two kinetochores.) So chromosomes in meiosis I have only one point of attachment to the spindle fibers and that means each chromosome can only be pulled towards one centrosome.

However, the chiasmata created in prophase I "lock" both chromosomes in the tetrad together like a single unit. Therefore, the two kinetochores, one on each chromosome, can pull in their "tug-of-war" just like in mitosis. That allows the chromosomes to line up between the centrosomes, as in mitosis, but in tetrads.

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