Mitosis

Prophase
• chromatin begins to coil and condense to form chromosomes each chromosome appears to have two strands (each containing a single molecule of DNA)
• each strand is called a chromatid
• each chromatid is attached to its sister chromatid at the centromeres
• at this stage, the number of chromosomes (containing a pair of chromatids) is considered to be equal to the number of centromeres
• the two chromatids are the result of DNA replication that takes place just before mitosis starts.
• the nuclear envelope disappears
• the nucleolus disappears
• in cytoplasm, the spindle apparatus forms
• eventually the spindle guides the separation of sister chromatids into the two daughter cells

Metaphase
• spindle grows and forms attachments to the chromosomes at the centromeres
• chromosomes move to an equatorial plate (metaphase plate) which is formed along the midline of the cell between the poles
• chromosomes are at their most condensed state now
• metaphase chromosomes can be stained and will show distinctive banding patterns
Anaphase
• centromeres divide to create two chromosomes instead of a pair of attached chromatids
• spindle fibers shorten and the sister chromosomes are drawn to the opposite poles of the cell
• poles of the spindle apparatus are pushed apart as the cell elongates
• anaphase results in the exact division of chromosome, distributing one complete diploid complement of genetic information to each daughter cell
Telophase
• nuclear envelopes reassemble and surround each set of daughter chromosomes
• nucleoli reappear inside the newly formed nuclei
• in animal cell, a furrow appears around the cell that eventually pinches the cell into two new cells
• in plants, a cell plate forms between the two daughter nuclei as the cell wall divides the cell
• chromosomes decondense in the daughter cells to become chromatin and the cells are once again in Interphase.