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4 Cards in this Set
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What are the stages of Mitosis? - in order and description of what is occuring
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(Interphase - cell growth and beginning of duplication)(Prophase - doubled chromosomes appear as sister chromatids joined at centromere/waist, centrosomes form spindle and separate)(Prometaphase - nuclear envelope is gone, spindles attach to chromosomes at centromeres, and move to center of cell)(Metaphase - spindle is fully formed, centromeres line up on plate, kineticores/protein structure of each sister chromatid align with the poles in opposite formation)(Anaphase - centromeres come apart & separate into sister chromatids forming daughter chromosomes, attached spindles shorten and unattached lengthen elongating the cell)(Telophase & Cytokenisis - T is reverse of prophase and nuleoi reappear, spindle disappears & chromatin fiber uncoils; C is division of cytoplasm, creates cleave furrow and pinches cell in 2)
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Understand the cell cycle
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Part of the process of division, it is an ordered sequence of events that occur in 2 main phases - Interphase and Miotic phase. Interphase has 3 parts: G1 when it grows, S where DNA is made, and G2 that has more growth and preps for division.MIOTIC phase is where it all happens - mitosis (division of nucleui and chromosomes), and cytokenisis (division of the cytopolasm). Once completed, the cell starts all over again...
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What are the stages of Meiosis? - in order and description of what is occuring
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Has 2 parts, M1 is when chromosomes separate, and M2 is when sister chromatids separate__(Interphase - same start as Mitosis)(Prophase 1 - cells coil(synapsis), chromatids pair up in structure know as tetrad, chromatids cross over, centrosomes form spindle and separate)(Metaphase 1 - chromosome tetrads form on plate, spindles attach to kineticores)(Anaphase 1 - sister chromatids pull apart while still attached to spindle at centromere)(Teolphase 1 - each set of chromatids are now formed and are considered a haploid, division occurs and preps for 2nd stage, without duplication) Meiosis 2 is basically same as mitiosis, but starts with haploid cells and forms finally forms 4 daughter cells with single set of chromosomes.
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Explain how crossing-over, random tetrad lineup(ind assortment), and random fertilization contribute to genetic varation in sexually reproducing organisms
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In the creation of a new sex cell the crossing over, random tetrad lineup and random fertilization make changes in the genes make up giving different traits to different genes thus creating more variations in the species. Crossing-over shuffles the non-sister chromatids, then the tetrads randomly attach to the poles, and in fertilization the millions of sperm each have different variations of the genes that also add to the differences.
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