Biology, Eighth Edition (Raven)

Chapter 12: Patterns of Inheritance

How Meiosis Works

Why is Meiosis Necessary? In order to produce haploid gametes, individuals must have cells that undergo cell division that does not produce daughter cells that are genetically identical to the parent. Otherwise the gametes would be diploid and a zygote formed from diploid sperm and egg would be tetraploid. The two stage process of meiosis reduces the number of chromosomes in the cell by half. One chromosome from each homologous pair is present in each gamete.

View the animation below, then complete the quiz to test your knowledge of the concept.


Centromeres divide in
A)mitosis and meiosis I.
B)mitosis and meiosis II.
C)meiosis II only.
D)meiosis I and meiosis II.
E)mitosis, meiosis I and meiosis II.

Which of the following describes meiosis II in humans?
A)4N -> 2N
B)2N -> 2N
C)2N -> 1N
D)1N -> 2N
E)1N -> 1N

Arrange the following events in the proper order in which they occur during meiosis I.

1 = Separation of homologous chromosomes
2 = Synapsis
3 = Crossing-over
4 = Independent assortment
A)1, 2, 3, 4
B)1, 3, 2, 4
C)2, 3, 1, 4
D)2, 3, 4, 1
E)2, 4, 3, 1

Germ-line cells are haploid but gametes are diploid.

Independent assortment occurs in prophase I.
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