Anaphase - Many of the events in telophase are the reverse...

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Anaphase When the chromosomes split at the end of metaphase, the chromosome number is doubled. For example, the number of chromosomes and chromatids during each phase in a human cell is: Phase # Chromosomes # Chromatids Prophase 46 92 Metaphase 46 92 Anaphase 92 92 Telophase 92 92 Chromosome movement Microtubules lengthen and shorten by the addition or removal of tubulin dimers. Click here for details in the chapter on cells. Kinetochore microtubules shorten in the region of the kinetochore, pulling the chromosomes apart. Polar microtubules push against each other and thus, push the two centrosomes apart. This, in turn, also pulls the chromosomes apart. The chromosomes move toward poles of cell. Cytokinesis (division of the cell) begins in anaphase. A cleavage furrow forms as actin filaments underneath the plasma membrane constrict in a band called the contractile ring. Two cells will be produced as this process continues. Telophase Telophase begins when chromosomes reach the poles of the daughter cells.
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Unformatted text preview: Many of the events in telophase are the reverse of prophase. The chromosomes uncoil, the nuclear membranes around daughter nuclei appear, the spindle apparatus breaks down, and the nucleolus reappears. Cytokinesis is completed as telophase ends. Interphase This is the non-dividing phase. During interphase, the nucleus is visible and the chromosomes are uncoiled and invisible. Interphase includes G 1 , S and G 2 . G 1 Each chromosome has one chromatid. The cell grows in size. Synthesis of organelles occurs. S This is when DNA synthesis occurs. G 2 Each chromosome has two chromatids. The synthesis of enzymes and other proteins in preparation for mitosis occurs during this period. Cells that permanently leave the cycle Some cells remain permanently in G 1 . Examples: skeletal muscle, nerve cells Some cells remain permanently in G 2 . Example: cardiac muscle Below: Whitefish blastula X 400...
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Anaphase - Many of the events in telophase are the reverse...

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