Mitosis
Prophase is the first phase of mitosis. The duplicated chromosomes condense nad become visible. The centrioles (located in the cytoplasm. helps organize spindle) move to opposite sides of the nucleus and help organize spindle (fanlike microtubule structure that seperates chromatids). The spindle attatches at a point called their centromere (the area where ach pair of chromatids are joined). The nucleus disappears and the nuclear envelope breaks down.
Metaphase is when the centromeres of the duplicated chromosome line up across the center of the cell. The spindle fibers connect the centromere of each chromosome to the two poles of the spindle.
Anaphase is when the centromers are pulled apart and the chromatids seperate to become individual chromosomes. The chromosome seperate into two groups near the poles of the spindle.
Telophase is the final stage of mitosis. During telophase, the chormosomes spread out into a tangle of chromatin. A nucelar envelope forms around each cluster of chromosomes. The spindle breaks apart, and a nucleolus becomes visible in each 'daughter' nucleus.
Definition: Mitosis is the splitting of the nucelus.