Cytokinesis / cell cleavage

Occurs simultaneously with the unfolding of the chromosomes and the formation of the nuclear envelope. It differs considerably in animal and plant cells.

In animal cells separation of daughter cells is produced by an equatorial constriction which involves a contractile mechanism at the cell cortex. This is achieved by a system of actin-like microfilaments. A dense structure called the midbody may be formed.

In plant cells cytokinesis starts with the formation of the phragmoplast, which comprises interzonal microtubules and Golgi vesicles. This structure is transformed into the cell plate, which separates the territories

of the daughter cells. Within the cell plate the primary cell wall is produced by a secretory mechanism consisting mainly of the pectin, which is contained in Golgi vesicles.