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9 Cards in this Set
- Front
- Back
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Cell cycle in eukaryotes |
The cell cycle costs of a period of growth & DNA replication,called interphase & a period of cell divs ion called mitosis Interphase is the phase in the cycle,normally longer than the whole of mitosis,unless cell is rapidly dividing All somatic (non sex) cells in the body contain 46 chromosomes in 23 homologous pairs So when a new daughter cell is produced it will also contain 46 chromosomes |
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Interphase |
●DNA replicates ●ATP synthesised ●Organelles synthesised including centrioles ●proteins synthesised |
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Mitosis (Nuclear Division) |
Important For: ●all org that need to produce genetically identical daughter cells ●Asexual Reproduction:single celled org divide to produce daughter cells e.g. paramecium ●Growth-multicellular org grow by producing new extra cells that are genetically identical to each other & the parent cell ●Repair- damaged cells need to be replaced by new ones that perform the same function so must be identical ●Replacement-red blood & skin cells need to be replaced
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Prophase (PMAT) |
●Replicated chromosomes shorten & thicken (supercoil) ●each chromosome consists of a pair of sister chromatids ●Nuclear envelope breaks down & disappears ●Centriole divides into 2 & moves to opposite poles to form spindle fibres (Protein)
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Metaphase (PMAT) |
●replicated chromosomes line up down the middle of the cell ●each chromosome is attached to a different spindle fibre by its centromere |
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Anaphase (PMAT) |
●replicas if each chromosome are pulled apart from each other towards opposite poles ●Identical sister chromatids are pulled to different poles by the shortening of the spindle fibre |
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Telophase (PMAT) |
●2 new nuclei are formed ●sister chromatids reach poles & are now chromosomes ●Spindle breaks down & dissappears ●Chromosomes Uncoil & can not be seen in a light microscope any more |
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Cytokinesis ( division of cytoplasm) |
●occurs between telophase & interphase
Animal ●microtubules form a "draw string" just inside the membrane which then fuses as it is pinched in
Plants ●microtubules direct vesicles to the middle of the cell to form a cell plate ●which forms a new cell wall ●new cell surface membrane is made on either side to enclose the 2 cells
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Graph to show the variation in mass of a diploid cell and the DNA within it during the cell cycle |
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