Mitosis

video frame of cell in interphase

Interphase: (between cell division). Here the cell is about to start entering mitosis. The centrosome (green) has duplicated. Microtubules (blue) grow out of the centrosomes. The centrosome and microtubules cannot be seen in the phase picture below, but are shown in the diagram, to show how these structures re-organise during mitosis.

drawing of a cell in interphase
video frame of cell in prophase

Prophase - the start of mitosis

Nuclear envelope breaks down, and chromosomes condense (light blue structures in the diagram opposite). Microtubules re-organise to form mitotic spindle. The centrosomes move to opposite ends of the nucleus to form the spindle poles.

drawing of a cell in prophase
video frame of cell in prometaphase

Prometaphase

Duplicated chromosomes (light blue in diagram opposite) move to the centre of the mitotic spindle (the 'equator'). See if you can identify the chromosomes in the phase micrograph below - they look black and are close to the equator.

drawing of a cell in prometaphase
video frame of cell in metaphase

Metaphase

Duplicated chromosomes (light blue) are aligned on the centre (equator) of the mitotic spindle. Notice how the whole structure has rotated, so that the poles are rotated by about 90 degrees compared to that in prometaphase.

drawing of a cell in metaphase
video frame of cell in anaphase

Anaphase

Chromosomes move to the poles (shown in green) of the spindle.

drawing of a cell in anaphase
video frame of cell in telophase

Telophase

Chromosomes have moved towards the poles, they will now start to decondense, and intact nuclei will start to reform.

drawing of a cell in telophase
video frame of cell in cytokineses

Cytokinesis

Cell is pinched in two, to form two new cells.

drawing of a cell in cytokinesis

The whole of mitosis lasts about 30 - 60 minutes in real time, here it is shown speeded up.

Have a look at dividing cells in a photo.