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Mitosis
is a process of nuclear division which produces two
genetically identical daughter cells. It takes place in 5 stages;
prophase, metaphase, anaphase, telophase and cytokinesis
Nuclear
envelope
begins to
disintegrate
In prophase, chromosomes shorten
and thicken (supercoil) and become
visible under a light microscope.
Each consist of a pair of sister
chromatids. The nuclear envelope
breaks down and disappears. The
centriole divides and the two
daughter centrioles move to the
cell poles and form the spindle.
Centrioles
begin to
move to the
poles of
the cell
DNA wraps around histone proteins to form
condensed, X-shaped, chromosomes
Centrioles are
at the poles
of the cell
In metaphase, the
chromosomes move to the
central region of the
spindle, the equator, and
each becomes attached to a
spindle thread by its
centromere.
A protein
spindle grows
from the
centrioles and
attaches to the
chromosomes at
the centromere
Chromosomes are lined up along the
equator of the cell
Centromeres
split
Spindles contract and shorten
In anaphase, the replicated
sister chromatids which make
up the chromosome are
Sister
separated form each other as
chromatids
the centromere splits. The
are pulled
spindle fibres shorten, pulling
towards
opposite poles the sister chromatids further
of the cell
away from each other towards
the poles.
Nuclear
envelope
reforms
around the
‘new’ nuclei
In cytokinesis, the cytoplasm
divides in two, forming two
identical daughter cells. Each
cell has the exact same genetic
information, and so is capable
of doing everything that the
parent cell could do. The cell
then returns to interphase.
In telophase, the separated sister
chromatids, which are now
chromosomes, reach the poles of
the cell. A new nuclear envelope
forms around each, and the
spindle breaks down and
disappears. The chromosomes
uncoil and decondense to reform
chromatin.