Describe the process of mitosis - KCSE Biology Essays

Occurs in somatic/body cells; through five main stages/phases:

Interphase/Resting stage;
intense internal activities occur in the cell at this stage in preparation for the division; the activities include; replication of each chromosome to multiply genetic material to retain chromosomal number in daughter cells; chromosomes appear as a diffuse tangle of threads (chromatin); synthesis of new cellular organelles; build-up of energy stores (ATP) to drive the entire cell division process;

Prophase; chromosomes become visible; as they shorten and thicken appearing as discrete strands (chromatids) lying parallel to each other; in animal cells, centrioles separate and move to opposite ends (poles) of the cell; they radiate from each of the ends forming spindle fibres; nuclear membrane begins to breakdown; nucleolus disappear;

Metaphase; Chromosomes migrate/move to the centre of the cell; and align themselves along the equatorial plane of the spindle; they get attached to the chromosomes, by their centromeres; nuclear membrane breaks down and disappears; spindle fibres lengthen; and attach to the centrioles at both poles forming asters;

Anaphase; chromatids separate at the centromere; shortening of the spindle fibres occurs; resulting in the chromatids migrating to opposite poles of the cell; spindle apparatus begins to disappear;

Telophase; final stage where chromatids reach the poles; become densely packed together and uncoil; a nuclear membrane forms around each mass/set of chromatids (now referred to as chromosomes); cytoplasm divides into two (cytokinesis); in animal cells, the cytoplasm divides by constriction of the cell membrane; while in plant cells, a cell plate forms within the cytoplasm and grows to separate the cell into two; spindle fibres disappear within the cytoplasm; and nucleoli reappear in the nuclei; of the two daughter cells formed at the end of telophase;