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Mitosis and Cytokinesis
Chapter 6.3
The Cell Cycle
The Cell Cycle is a repeating sequence of cellular growth & division during the life of an organism.
Pre Mitosis- InterphasePhase of cell division when the cell
copies its DNA grows larger & prepares to divide.
A cell spends 90% of its lifetime in Interphase
There are 3 sections of Interphase: G1, S, and G2
Interphase- G1 Phase
“G1” Phase= First Growth phase90% of the cells life is spent in the G1 phase\Carries out routine functions, growsSome muscle and nerve cells never leave this
stage… what does this mean?
Interphase- “S” phase“S” phase = Synthesis PhaseDNA is copied
Interphase- G2 Phase
“G2” Phase= 2nd Growth PhaseMicrotubules form to prepare for divisionMicrotubules- Hollow protein fibers that help
pull chromosomes apart
Mitosis!Mitosis- Process of cell division where the
nucleus dividesOccurs in 4 Steps
ProphaseMetaphaseAnaphaseTelophase
Mitosis Stage 1- ProphaseNucleus Breaks DownSpindle Forms to pull microtubulesChromosomes are visible
Mitosis Stage 2- MetaphaseChromosomes line up at the equator
Mitosis Stage 3- AnaphaseChromosomes splitChromosomes are pulled to opposite sides of
the cell
Mitosis Stage 4- TelophaseThe Nucleus reappearsThe cell begins to split
Post Mitosis- CytokinesisThe cell splits into two cells by:
Cleavage Furrow- occurs in animal cells/ cells without cell walls
Cell Plate Formation- occurs in plant cells/ cells with cell walls
IMPORTANT !!!!!!!!!Interphase and Cytokinesis are NOT
considered Mitosis!MITOSIS is ONLY…
PROPHASEMETAPHASEANAPHASETELOPHASE