Bio cell cycle and cell division
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Transcript of Bio cell cycle and cell division
Sister chromatids of each chromosomes separate completely to become daughter chromosomes.
New chromosomes move towards the poles along the path of their spindle fibers
Centromeres lead the path and arms trail behind
Events occurring during anaphase
Centomeres split and chromatids separate
Chromatids move to opposite poles
Final stage of mitosis.
Chromosomes that have reached their respective poles decondense and lose their individuality.
Events occurring in telophase
Chromosomes cluster at opposite spindle poles and their identity is lost as discrete elements.
Nuclear envelope assembles around the chromosome cluster
Nucleolus, golgi complex, ER reform.
It is the division of cytoplasm of parent cell into two daughter cells
Cytokinesis in animal cells
In animal cell it is achieved by the appearance of a furrow in the plasma membraneThe furrow gradually deepens and ultimately joins the centre dividing the cell cytoplasm into two
Wall formation starts in the centre of the cell and grows outward to meet the existing lateral walls.
Cytokinesis in plant cells
Plant cells are enclosed by relatively inextensible cell wall.Therefore they undergo cytokinesis by a different mechanism.
Wall formation starts in the centre of the cell and grows outward to meet the existing lateral walls.
Formation of new cell wall begins with the formation o a simple precursor, called the cell plate that represents the middle lamellabetween the walls of two adj cells.
In some organisms karyokinesis is not followed by cytokinesis as a result of which multinucleate condition
arises leading to the formation of
syncytium
GROWTH: New somatic cells are formed by mitosis. Therefore, mitosis helps in growth and development of multicellular organisms
REPAIR: Repair of the body takes place because of the addition of cells by mitosis.The cells of the upper layer of the epidermis, cells of lining of the gut, and RBCs are constantly being replaced