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Anaphase 1
The fourth stage of the first meiotic division (meiosis I), during which maternal and paternal homologous pairs are separated on microtubules.
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Anaphase 2
The fourth stage of the second meiotic division (meiosis II), during which either maternal or paternal sister chromatids are separated on microtubules.
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Chiasma
The region of physical linkage between maternal and paternal homologous pairs during genetic reassortment. Marks the location of crossover between two nonsister chromatids.
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Diploid number
The total number of chromosomes present in a cell.
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Gametes
Cells with the haploid number of chromosomes. Gametes are created out of germ cells. The sperm and eggs involved in sexual reproduction are gametes.
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Genetic Reassortment
A process in which DNA packaged as a chromosome is broken and fragments are exchanged with another independent chromosome. Occurs during prophase 1 of meiosis.
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Germ cell
Cells that lead to the production of gametes. Produced by meiosis.
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Haploid number
The number of unique chromosomes or homologous pairs in a cell. Half the diploid number.
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Homologous pair
Refers to two similar chromosomes in a diploid cell. One chromosome is derived from the father gamete cell and the other from the mother gamete.
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Meiosis
A type of cellular reproduction that results in the formation of four haploid cells from one diploid cell. Contains two cellular divisions that follow only one round of DNA replication. The type of reproduction that produces germ cells.
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Metaphase 1
The third stage of the first meiotic division (meiosis I), during which chromosomes align at the center of the cell by way of microtubule force.
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Metaphase 2
The third stage of the second meiotic division (meiosis II), during which chromosomes align at the center of the cell by way of microtubule force.
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Microtubule
One of three protein components of the cytoskeleton. Long, cylindrical structures approximately 25 nanometers in diameter. Extend from the centrosome to all parts of the cell, forming tracks on which organelles can travel within the cell.
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Prometaphase 1
The second stage of the first meiotic division (meiosis I), during which the nuclear envelope breaks down, allowing microtubule access to chromosomes.
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Prometaphase 2
The second stage of the second meiotic division (meiosis I), during which microtubules attach to chromosomes.
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Prophase 1
The first stage of the first meiotic division (meiosis I), during which genetic reassortment takes place. Can be very long occupying up to 90% of the entire duration of meiosis.
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Prophase 2
The first, brief stage of the second meiotic division (meiosis II), during which condensed chromosomes are visible.
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Sister chromatid
Refers to the copy of a chromosomes that results from DNA replication and is still closely linked to its original.
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Somatic cell
Any plant or animal cell that is not a germ cell. The class of cell formed during mitosis.
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Telophase 1
The fifth and final stage of the first meiotic division (meiosis I), during which chromosomes arrive at the poles of the cell and begin to recondense.
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Telophase 2
The fifth and final stage of the second meiotic division (meiosis II), during which chromosomes arrive at the poles of the cell, the nuclear envelope begins to reform, and the chromosomes begin to recondense.
