Metaphase The second stage of mitosis in which chromatid pairs line up on the

Metaphase the second stage of mitosis in which

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Metaphase - The second stage of mitosis, in which chromatid pairs line up on the metaphase plate of the cell. 3. Anaphase - The third stage of mitosis in which the chromatids that have separated at the centromeres move to opposite poles of the cell. 4. Telophase – The final stage, begins after chromosomal movement stops. The identical sets of chromosomes, now at opposite poles of the cell, uncoil and revert to the threadlike chromatin form. A nuclear envelope forms around each chromatin mass, nucleoli reappear in the identical nuclei, and the mitotic spindle breaks up V. cytoplasmic division: cytokinesis - division of a cell's cytoplasm and organelles into two identical cells; begins in late anaphase 1. cleavage furrow - a slight indentation of the plasma membrane, and is completed after telophase; appears midway between the centrosomes and extends around the periphery of the cell; The ring constricts the center of the cell, like tightening a belt around the waist, and ultimately pinches it in two. D. reproductive cell division I. meiosis - A type of cell division that occurs during production of gametes, involving two successive nuclear divisions that result in cells with the haploid (n) number of chromosomes. II. haploid cell (n) -Having half the number of chromosomes characteristically found in the somatic
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cells of an organism; characteristic of mature gametes. Symbolized n. III. meiosis I - begins once chromosomal replication is complete, consists of four phases: prophase I, metaphase I, anaphase I, and telophase I 1. prophase I - an extended phase in which the chromosomes shorten and thicken, the nuclear envelope and nucleoli disappear, and the mitotic spindle forms. i. Synapsis - the two sister chromatids of each pair of homologous chromosomes pair off ii. Resulting four chromatids form a structure called tetrad iii. Parts of the chromatids of two homologous chromosomes may exchanged with one another 1. crossing-over - an exchange between parts of nonsister (genetically different) chromatids; the resulting cells are genetically unlike each other and genetically unlike the starting cell that produced them; results in genetic recombination (formation of new combinations of genes) 2. Metaphase I – the tetrads formed by the homologous pairs of chromosomes line up along the metaphase plate of the cell with homologous chromosomes side by side 3. Anaphase I – the members of each homologous pair of chromosomes separate as they are pulled to opposite poles of the cell by the microtubules attached to the centromeres. The paired chromatids, held by a centromere, remain together. 4. Telophase I - The net effect of meiosis I is that each resulting cell contains the haploid number of chromosomes because it contains only one
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