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Mitosis
Objective: I can identify
and describe the stages of
mitosis.
Warm Up: What makes a
cancer cell so dangerous?
Cell life cycle: changes cell goes
through from time formed until it
divides
2 major periods:
 1. Interphase: cell grows and carries
on usual metabolic activities
- longest phase of cycle
- very active
-DNA is duplicate toward end
2. Cell division: It reproduces itself
- fx : more cells for growth and repair
processes
Interphase
 G1 Phase: synthesis of RNA
and proteins .Period of
growth and development
for the cell.
S phase ( Synthesis): the
chromosomes of the cell
are copied
G2 Phase : cell grows in
Preparation for cell division).
Any repairs
Mitosis
Cells replicated Genetic
material separates & cell
prepares to split into two
cells
Stages of Mitosis
4 Stages
Prophase
Metaphase
Anaphase
Telophase
Stages of Mitosis
Prophase-
st
1
stage
Stage where dividing cells spend the
most time
The cells chromatin tightens, or
condenses into chromosomes
The chromosomes are shaped like an
X
Each chromosome is a single
structure that contains the
genetic material
Each half of this X is called a sister
chromatid.
Sister chromatids- structures that
contain identical copies of DNA
Centromere: structure at the
center of the chromosome where
the sister chromatids are attached
The centromere is important , it
ensures that a complete copy of
replicated DNA will be part of the
daughter cells at the end of the
cycle
Nuclear envelope breaks down
Microtubule structures called
spindle fibers form in the
cytoplasm
*in animal cells another pair of
microtubule structures called
centrioles migrate to the ends or
poles of the cell.
Metaphase- 2nd stage
Sister chromatids are pulled along
the spindle apparatus toward the
center and line up in the middle of
the cell along the equatorial plate
One of the shortest stages
Anaphase- 3rd stage
 Chromatids pulled apart
 Microtubules of the spindle apparatus begin to
shorten
 Sister chromatids separate into 2 identical
chromosomes
 All the sister chromatids separate simultaneously
 At the end- the microtubules move the chromosomes
toward the poles of the cell.
Telophase – Last stage
Chromosomes arrive at the poles
of the cell and begin to relax, or
decondense
A new nuclear membrane starts
to form around each group.
Chromosomes uncoil, and the
spindle disappears.
Cytokinesis
Divide the cytoplasm
Results in 2 cells each with identical nuclei
2 genetically identical cells
T.O.D.
List the stages of Mitosis