CELL
DIVISION
Introduction:
Cells
are the smallest functional units of the body. They are grouped together to
from tissues, each of which has a specialized function.(eg) blood, muscle ,bone.
Different tissues are grouped together to from organs, e.g heart, stomach,
brain. Organs are grouped together to form systems. Each of which performs a
particular function that maintains homeostasis and contributed to the health of
the individual.
Cell
division:
Most
body divide by mitosis a process that results in two new genetically identical
daughter cells. Formation of gametes ova & Spermatozoa takes play by
meiosis and four daughter cells are genetically different from the parent cell
and each other.
The period between cell division is
known as interphase towards the end of interphase. The chromation replicates
and becomes tightly coiled forming double chromosomes called chromatids in
preparation for cell division in human cells there are 46 chromosomes. The two
chromotids of each chromosome are joined at the centromere.
Mitosis:
This
is a continuous process involving four distinct stages seen by eight micros
copy.
Prophase:
During
the stage the chromotids become visible within the nucleolus and the mitotic
apparatus appears. This consist of two centrioles separated by the micro tubules
mitotic spindle which is formed from microtubules the centrisotes migrate one
to each end of the cell & the nuclear envelope disappears.
Metaphase:
The
chromatids align on the centre of the spinde, attached by this centromere.
Anaphase:
The centromere spererte and one of each pair
of sister chromaticls migrates to each pole of the spindle as the microtubules
that form mitotic spindle contract.
Telophase:
The
mitotic apparatus disappears the chromosomes uncoil and the nuclease envelope
reform. Telophase.the cytoplasm and plasma membrance divide in half forming two
identical daughter cells. The orangelles of daughter cells are imcomplete at
the end of cell division but they develop as the cell matures during
interphase.
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