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20 Cards in this Set
- Front
- Back
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what are the four centromere placements
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metacentric
submetacentric acrocentric telocentric |
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centromere location for metacentric
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middle
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centromere location for submetacentric
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between middle and end
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centromere location for acrocentric
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close to end
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centromere location for telocentric
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at end
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what are the four parts of the cell cycle
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G1
S G2 M |
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what occurs during S phase
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cell synthesis (replication of DNA of each chromosome)
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what is G0 phase, when does it occur
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occurs during G1 phase
-when cell withdraws from the cell cycle and become quiescent |
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how many chromatids before and after replication
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before: 1
after: 2 |
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what is cohesin
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holds sister chromatids together
-forms during S phase |
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what is kinetochore
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where spindle fibers/microtubules attach to centromere
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what is shugoshin
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protects cohesin from degrading at centromeric region
-protects during metaphase, is overcome during anaphase |
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define bivalent
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pair of homologous chromosomes
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what are the five phases of prophase
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1. leptonema
2. zygonema 3. pachynema 4. diplonema 5. diakinesis |
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what occurs during leptonema
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-chromatin begins to condense
-homology search begins (chromtin searches for homolog to make a pair) |
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what occurs during zygonema
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-initial pairing of homologous pairs (rough pairing)
-bivalents form -synaptonemal complex begins to form |
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what occurs during pachynema
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-synapsis occurs: close pairing of homologs
-tetrads form -each homolog evident as double structure |
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what occurs during diplonema
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-chiasmata form (crossing over between non-sister chromatids)
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what occurs during diakinesis
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-chromosomes pull apart, but non-sister chromatids remain connected at chiasmata
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does reductive division occur during Meiosis I or II?
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Meiosis I
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