Mitosis

Mitotis is the mechanism used by cells to replicate DNA and produce identical cell copies. New cells enlarge and can differentiate into the various tissues of actively growing plant structures.

Mitosis involves a number of definable stages. Cells replicate their DNA, condense the DNA into chromosomes, and separate their chromatids (copies of chromosomes) to daughter cells.

Roll over boxes to the right to view examples of cells of a root meristem in various stages of mitosis. Cell divisions start with interphase.

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Anaphase

During anaphase the two sets of chromatids (now chromosomes) separate to opposite poles. A cell plate, not visible now, will eventually form between the two cells during telophase.

Early Telophase

During telophase the nuclear membranes reform. Nuclei with nucleoli become visible in daughter cells. Now, a faint cell plate is just visible between the nuclear masses.

Late Telophase

In late telophase, new nuclear membranes form in each daughter cell. The cell plate, now more visible continues forming as cytokineses, the separation of cytoplasm progresses.

Prophase

During prophase DNA condenses and chromatid pairs appear in a circular mass within the nucleus. The nuclear membrane and nucleoli are still intact during early prophase but will disappear as prophase progresses into metaphase.

Interphase

Although described as the resting stage (from the standpoint of cell division), interphase cells are hardly "resting". These are the normal, active cells. DNA is dispersed and genes are actively being transcribed. Enzyme production and activity is at its highest level and these cells are therefore, most active metabolically. Interphase cells possess a well-defined nucleus with a nucleolus.