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16 Cards in this Set
- Front
- Back
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What is 'Topoisomerase'?
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Enzymes that unwind and wind DNA, in order for DNA to control the synthesis of proteins, and to facilitate DNA replication. The enzyme is necessary due to inherent problems caused by the DNA's double helix.
(Unwraps knots) |
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What is the name for the long arm of a chromatid?
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Q arm
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What is the name for the short arm of a chromatid?
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P arm
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What are the four stages of prophase 1?
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Lepotene, zygotene, pachytene, diplotene
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What happens during lepotene in prophase I?
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Individual chromosomes begin to condense
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What happens during zygotene in prophase I?
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Chromosomes approximately line up with each other into homologous chromosome pairs (bivalents). Synapsis (pairing/coming together) of homologous chromosomes takes place
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What is a bivalent?
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A pair of homologous chromosomes
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What happens during the pachytene phase in prophase I?
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Chiasmata - Nonsister chromatids of homologous chromosomes randomly exchange segments of genetic information (crossing over/chiasmata)
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What is the 'synaptonemal complex'?
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A protein structure that forms between two pairs of homologous chromosomes during meiosis and that is thought to mediate chromosome pairing, synapsis, and recombination (crossing-over)
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What happens during diplotene in prophase I?
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Synaptonemal complex degrades and homologous chromosomes separate from one another a little. The chromosomes themselves uncoil a bit, allowing some transcription of DNA.
HChroms of each bivalent remain tightly bound at chiasmata and centromere |
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What is Mendel's first law?
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Segregation of Characteristics - only one characteristic can be expressed in a pair (concept of dominance)
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What is the key idea about inheritance that Mendel suggested?
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That it is done by particles, not fluids
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What was Mendel's second law?
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Law of independent assortment - different genes assort independently of one another during gamete formation
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Men do/do not pass X chromosome onto their sons
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Do NOT, they pass the Y as the mum doesn't have a Y!
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What are the two Hardy-Weinberg equations? What are the conditions for it working?
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p + q = 1
p^2 + 2pq + q^2 = 1 No selection/mutation Large pop No migration HW can be used to check if any of these assumptions are false |
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What happens during the last stage of Prophase I, diakinesis
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Nuclear membrane braks down, chiamata slip to the ends of chromosome arms
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