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Definition
| members of a chromosome pair that contain the same genes and that pair during meiosis, creating sister chromatids held together at the centromere |
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Term
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| can be metacentric (centromere at center), submetacentric (one end shorter), acrocentric (one end a lot shorter), and telocentric (centromere at end). Important for cell division |
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Definition
| chromosomes (2 sister chromatids) condense, nucleolus shrinks, and the spindles assemble outside the nucleus |
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Definition
| nuclear envelope breaks down, spindle enters nuclear area, kinetochores bind to each centromere (where spindle fibers attach) |
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Term
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Definition
| kinetochore microtubules orient chromosomes on the metaphase plate |
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Definition
| joined sister chromatids separate=>2 daughter chromosomes. Daughter chromosomes pulled to opposite poles by microtubules |
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Definition
| chromosomes begin to uncoil, nuclear envelope forms, spindles disappear, nucleolus reforms |
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Definition
| composed of leptonema, zygonema, pachynema, and diplonema |
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Definition
| extended chromosomes begin to condense. Cell now committed to meiosis |
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Term
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Definition
| homologous pairs of chromosomes find each other and align along their lengths=>synapsis-formation along the length of a zipperlike structure (synaptonema complex) that aligns the two homologs base pair for base pair |
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Term
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Definition
| synapsed sets of homologous chromosomes are now called a bivalent/tetrad. Step at which crossing over occurs |
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Definition
| synaptonema complex disassembles, homologous chromosomes begin to move apart, now attached at only chiasmata |
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Definition
| chromosomes condense even more |
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Definition
| nucleoli disappear, nuclear envelope breaks down, spindle enters nuclear area. Kinetochores attach to both sister kinetochores |
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Definition
| kinetochores align tetrads on the metaphase plate |
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Term
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Definition
| chromosomes in each tetrad separate, forming 2 dyads. Homologous chromosomes have segregated from each other, but sister chromatids remain attached |
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Term
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Definition
| dyads complete migration to opposite poles, spindle disassembles |
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Term
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Definition
| just like mitosis. Daughter chromosomes pulled to opposite poles. Separated chromatids are now considered chromosomes in their own right |
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Term
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| XO individuals. Female, providing evidence for Y chromosome mechanism of sex determination (as opposed to # of x chromosomes) |
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Definition
| XXY, providing evidence for Y chromosome mechanism of sex determination |
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Term
| Dosage compensation and Lyon hypothesis |
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Definition
| Humans regulate the effects of the X chromosome (since males have 1 copy and females have 2) by inactivating one x chromosome in females. This process, called lyonization, produces an inactive x chromosome called a barr body. Which is is inactivated is randomly decided in every cell |
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Term
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Definition
| copies of a gene separate when creating gametes |
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Definition
| different genes separate independently of one |
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