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Mitosis in Action
Let’s Explore the Stages of Mitosis
What is Mitosis?
• Mitosis is cell division where
the replicated (cloned)
genetic material in a parent
cell is equally distributed to
two daughter cells.
What is Mitosis?
• Mitosis allows organisms to
grow, increase their size by
adding more cells &
• Replace damaged cells.
The Stages of Mitosis
• Interphase (not a true phase of mitosis)
• prophase
• metaphase
• anaphase
• telophase
Interphase
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The phase between cell divisions
There is still a lot going on.
The cell puts on mass.
The DNA makes a “photocopy” of
itself. Therefore, the # of chromosomes
has doubled in number. They are in the
form of thin, stringy CHROMATIN!
Spindle fibers will extend
from the centromeres in
later stages.
Chromatin is a long stringy form for DNA
found in the Interphase Stage
Prophase
• 1st TRUE step in mitosis.
• The stringy chromatin condenses into
individual chromosomes. Each
chromosome contains 2 chromatids
joined at a centromere.
• The nuclear membrane breaks down.
• Spindles form at opposite ends of the
cell.
Anatomy of Chromosomes
Kinetochores are fibers
that will attach to the
spindles.
The coiled chromatin
become the two
chromosomes (2 pairs of
chromatids) attached at the
centromere.
Metaphase
• The spindle fibers extend from the
poles of the cell to the center line.
• The chromosomes line up at the center
line of the cell.
• Spindle fibers attach to the
kinetochores at the centromeres on
each side of the chromatids.
Anaphase
• The paired chromatids begin to
separate and move toward the
poles.
• Each of the separated pairs of
chromatids are a full chromosome.
• The poles of the cell stretch further
apart to make the cell longer.
Telophase
• Nuclear membranes begin to form
around the chromosomes at the
opposite poles of the cell.
• The chromosomes uncoil to
become stringy chromatin fibers
again (the normal form of DNA)
Cytokinesis
• The cytoplasm and organelles
separate into two equal portions.
• The plasma membrane pinches
in to form two separate, new
daughter cells.
Try to identify the stages:
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