Mitosis is one part of a cell cycle; the others are G1, S and G2 in that order. In the first stage (G1) cell growth occurs and the proteins and organelles necessary for cell division are produced. During the S phase, the DNA is copied within the nucleus (the nuclear membrane does not break down). Then in the G2 phase the remaining changes needed for cell division occur. The the cell enters mitosis. In prophase, the nuclear membrane breaks down, in metaphase the chromatids (two copies of DNA made in S phase) line up on the cell equator, in anaphase the chromatids are pulled apart by the spindle fibres to opposite sides of the cell, and in telophase the two new nuclear membranes are formed. Only then does cell division occur, and it is called cytokinesis (not mitosis). So, mitosis is only one stage in cell division, which can be considered a form of asexual reproduction. Commonly, though technically incorrect, the entire process is referred to as mitosis.
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