(a) Describe the main stages of mitotic division. (b) State four ways in which mitosis...

Explanation

(a) Main stages of mitotic division:

Prophase-

• Chromosomes appear as two threads/chromatids
• chromatids are long thin and/later become shorter and thicker; and joined together at the centromere; the nuclear memberane; and the nucleolus disappear
• spindle fibres form in the cytoplasm; with a pair of centrioles; one at each pole.

Metaphase:

• spindle formation is completed
• the chromosomes are arranged at the equator of the spindle
• attached by their centromeres; centromeres divide; and begin to move apart. Anaphase
• The paired chromatids are pulled apart/separated
• migrate/move towards opposite poles
• spindle fibres shorten; chromatids reach the poles.

Telophase -

• Fibres disappear, nuclear materials and nucleolus are formed
• bounded by nuclear membrane
• the cell constricts
• to form two daughter cells.

(b) Importance of mitosis:

• Promotes cell growth
• replacement/repair of damaged tissues
• basis of asexual/ vegetative reproduction
• produces genetically identical offspring
• which are identical to the parents
• maintains the diploid number of the chromosome of the cell.