Cell Cycle & Chromosomes
Mitosis
THE CELL CYCLE
CHROMOSOMES AND
CENTROMERE POSITION
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Chromnosmes and
centromeric positions
The chromosomes to the
right represent
chromosomes before the
S-Phase of the cell cycle.
Mitosis and Meiosis are
terms that describe nuclear
division and are Eukaryotic
characteristics
CHROMOSOMES
TO
SISTER CHROMATIDS
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The formation of
sister chromatids
occur during the Sphase of the cell
cycle.
This is not visible
until Prophase and\or
Metaphase
INTERPHASE
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During interphase the
only thing that is visible
are the Nucleolus and
the Nuclear Membrane.
If we could see
chromsomes they would
look like the
chromsomes below the
cell which is before the
S-phase in the cell
cycle. Sister chromatids
have not been
synthesized.
MITOTIC - PROPHASE
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Give all the sequence of
events that occur in
prophase. These things do
not all occur at once.
Prophase is a gradual
process.
Nuclear membrane and
Nucleolus disappears.
In Animals centrioles
migrate to opposite poles
and aster rays radiate
about the centrioles.
Spindle fibers are visible
and are attached to
centromeres
MITOTIC - METAPHASE
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Chromsomes align
in the middle of the
cell.
MITOTIC - ANAPHASE
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The centromere
divides and
chromosomes
migrate to opposite
poles.
Another way of
describing this
stage is chromatids
separate and
migrate to opposite
poles.
MITOTIC - TELOPHASE
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Chromosomes reach
their poles and
cytokinesis begin
The events that occur in
prophase actually
reverse themselves in
Telophase.
Nucleolus and Nuclear
membrane reappears.
Spindle fibers
disappears.
Chromsomes become
invisible.
CYTOKINESIS IN ANIMALS

FORMATION OF
THE CLEAVAGE
FURROW OCCURS
IN ANIMAL CELLS
CYTOKINESIS IN PLANTS
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FORMATION OF
THE CELL PLATE
OCCURS IN PLANT
CELLS
INTERPHASE
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Just prior to the onset of
meiosis, DNA will
replicate.
The result is the
formation of sister
chromatids. As the
arrow indicates: Sister
chromatids are formed
after DNA replication.
What is the genotype
and chromosome
number.
Meiotic Prophase I
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Prophase I of Meiosis
is divided into five (5)
different substages
Leptotene
(Threadlike)
Zygotene (synapsis)
Pachytene (Recomb)
Diplotene (Chiasma)
Diakinesis