Cell cycle
Biology 3 Kawashima
Philippine Science High School
SY 2009-2010

Roles of Cell Division
Reproduction
Growth and Development
Renewal and Repair

What happens in cell division?
Duplication
Cell growth of genetic Fission
material

90% of the cell
Cell growth
cycle
Interphase
Checkpoints for
DNA synthesis
cell division

Interphase Mitotic Phase
G1 Prophase
Metaphase
S
Anaphase
G2 Telophase

Genome Chromosome Chromatin
• All genetic • Condensed • Uncondensed
information DNA state of DNA
packaging molecule
• Single DNA
molecule

Chromatin condenses
during prophase
• Nucleoli disappear
• Duplicated
chromosomes appear as
sister chromatids joined
at the centromere
• Microtubules begin to
extend from the
centrosome
• Lengthening of
microtubules propel
centrosomes to move
away from each other

Sister chromatids organize
during prometaphase
• Nuclear envelope
fragments
• Sister chromatids
develop a kinetochore –
a protein structure found
at the centromere
• Microtubules interact
with sister chromatids at
their kinetochores

Sister chromatids align at
the metaphase plate
during metaphase
• Metaphase plate an
imaginary plane
equidistant between the
poles
• Centrosomes now at
opposite ends of the cell
• Each chromosome has
numerous kinetochore
microtubules attached
• Longest stage of mitosis

Sister chromatids separate
during anaphase
• Liberated chromosomes
move towards the poles
through “walking”
centromere region first
• Nonkinetochore
microtubules lengthen
elongating the cell

Chromosomes become less
condensed during
telophase
• Two daughter nuclei
form
• Nuclear envelop reforms,
arising from the
endomembrane system
• Division of one nucleus
into two genetically
identical nuclei – mitosis
– is now complete

Cytokenesis is the division
of the cytoplasm
• Cytokenesis begins in
telophase
• In animals, formation of
cleavage furrow
“pinches” the cell into
two
• In plants, a cell plate
forms to divide the
cytoplasm into distinct
cells

Read on Cell Cycle Checkpoints
and Cancer