Term
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Definition
| sex cells divide to produce gametes interphase, meiosis I, meiosis II two divisions sexual reproduction |
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Term
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Definition
chromosomes condense
synapsis
chromatids within a pair wrap around each other
now follows similiar pattern to prophase in mitosis |
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Term
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Definition
| each chromosome pairs up with its bivalent (homologous pair/tetrad) |
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Term
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Definition
| a pair of two identical chromosomes |
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Term
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Definition
the place where chromatids within a pair wrap around each other
at the chiasmata, chromosomes may break and reform with other chromosomes (exchanging parts) |
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Term
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Definition
bivalents arrange themselves on cell equator with each of the pair orientated to opposite poles (random process)
sprindle fibres attatched to centromeres contract, pulling chromosomes apart as much as centromere will allow |
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Term
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Definition
spindle fibres contract
sister chromatids remain attatched at centromeres
homologous chromosomes separate and move to poles |
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Term
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Definition
chromosomes reach opposite poles
each pole now has haploid set of chromosomes
nucleolus and nuclear membrane reform around each group
spindle fibres disappear
cytokinesis occurs - two haploid daughter cells formed |
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Term
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Definition
| same as mitosis but two cells instead of one, so four daughter cells produced instead of two |
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Term
| Random elements of meiosis that lead to genetic variation (3) |
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Definition
production and fusion of gametes - gametes which fuse are random
random assortment of chromosomes during metaphase
crossing over during prophase I |
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Term
| Chromosome numbers before and after divisions (3) |
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Definition
diploid parent cell - 46 chromosomes - doubles to 92
two haploid daughter cells with 46 chromosomes
four haploid progeny cells with 23 chromosomes
progeny cells need to fuse to make a zygote |
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