Illustration showing the five stages of mitosis. The single cell then pinches in the middle to form two separate daughter cells each containing a full set of chromosomes within a nucleus.A membrane forms around each set of chromosomes to create two new nuclei.At each pole of the cell a full set of chromosomes gather together.The sister chromatids are then pulled apart by the mitotic spindle which pulls one chromatid to one pole and the other chromatid to the opposite pole.The mitotic spindle fibres attach to each of the sister chromatids.The centrioles are now at opposite poles of the cell with the mitotic spindle fibres extending from them.The chromosomes line up neatly end-to-end along the centre (equator) of the cell.The mitotic spindle, consisting of the microtubules and other proteins, extends across the cell between the centrioles as they move to opposite poles of the cell.At the end of prophase the membrane around the nucleus in the cell dissolves away releasing the chromosomes.The chromosomes pair up so that both copies of chromosome 1 are together, both copies of chromosome 2 are together, and so on.Each chromosome is composed of two sister chromatids, containing identical genetic information.The chromosomes condense into X-shaped structures that can be easily seen under a microscope.During interphase, microtubules extend from these centrosomes.Outside of the nucleus are two centrosomes, each containing a pair of centrioles, these structures are critical for the process of cell division.This ensures that each sister chromatid is no longer genetically identical. Next, the chromosomes swap genetic material with one another, in a process known as crossing over. Each homologous pair of chromosomes lines up carefully so their genes are aligned. The DNA in the cell is copied in preparation for cell division, this results in two identical full sets of chromosomes. Question: Why do you think that the chromosomes condense before mitosis This problem has been solved Expert Answer. During prophase I, the chromosomes condense and form homologous pairs.If not corrected in time, mistakes made during mitosis can result in changes in the DNA that can potentially lead to genetic disorders.The major purpose of mitosis is for growth and to replace worn out cells.During mitosis one cell divides once to form two identical cells.
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