Download Mitosis

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What would happen if cells split in two with
any preparation?
Would the two new cells survive?
NO!
Every cell must first copy its genetic
information before it can divide, so each new
daughter cell will get one complete copy of
genetic information
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Pass genetic information
from one generation of
cells to the next
Made up of DNA
(which carries the cell’s
coded genetic
information) and
proteins
The cells of every
organisms have a
specific number of
chromosomes
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Human somatic (body)
cells = 46 chromosomes
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Chromosomes are not visible in most
cells, because they are spread out
throughout the nucleus.
At the beginning of cell division, the
chromosomes condense and become
visible.
Before cell division, each
chromosome is replicated (copied) to
form two identical sister chromatids
attached in the center by a
centromere.
Ends of chromosomes are called
telomeres
Section 10-2
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Cell Cycle
The cell cycle represents recurring events that take place in the
period of time from the beginning of one cell division to the
beginning of the next. In addition to cell division, the cell cycle
includes periods when the cell is growing and actively
producing materials it needs for the next division.
1. Why is the cell cycle called a cycle?
2. Why do you think that it is important for a cell to grow in size during its
cell cycle?
3. What might happen to a cell if all events leading up to cell division took
place as they should, but the cell did not divide?
Go to
Section:
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The cell must go through a series of events to
grow and divide.
During the cell cycle, a cell grows and
differentiate, prepares for division, and divides
to form two daughter cells, which each then
begin the cycle again.
Eukaryotic cells use mitosis to divide.
Growth factors can stimulate cells to move
through the cell cycle more rapidly, and other
factors induce cells to differentiate and stop
moving through the cell cycle.
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The cell cycle consists of 4
phases:
G1: cell growth, increase in
size and synthesize new
proteins and organelles
(biochemical and biosynthetic
activity)
 S: copy chromosomes (DNA
replication or synthesis)
 G2: preparation for mitosismore organelles and
molecules are produced
 M: mitosis (nuclear division)
& cytokinesis (cytoplasmic
division)
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Section 10-2
Cell Cycle
includes
G1 phase
Go to
Section:
Interphase
M phase
(Mitosis)
is divided into
is divided into
S phase
G2 phase
Prophase
Metaphase
Anaphase
Telophase
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A long period of cell growth in between cell
divisions = G1, S, and G2 phases
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The process of nuclear division
that forms two identical nuclei
with the same number and type
of chromosomes as the original.
Nuclear division in part of the M
phase
Other part of the M phase is
cytokinesis (cytoplasmic division)
Mitosis is divided into 4 stages:
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Prophase
Metaphase
Anaphase
Telophase
Remember: Please Mom Another Tart
http://www.johnkyrk.com/mitosis.html
Section 10-2
G1 phase
M phase
S phase
G2 phase
Go to
Section:
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Chromosomes become visible, condense and separate
Centrioles (two tiny structures located in the cytoplasm near the
nuclear envelope) separate and go to opposite sides of the cell
Spindle apparatus (fan-like microtubule structure) helps separate
the chromosomes
Condensed chromosomes become attached to fibers in the spindle
at a point near the centromere of each chromatid.
The spindle fibers attach themselves to each chromosome with a
structure called a kinetochore.
Nucleolus disappears and nuclear envelope breaks down
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Chromosomes line up across the center of the
cell known as the metaphase plate
Microtubules connect the centromere of each
chromosome to the poles of the spindle
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Sister chromatids separate becoming individual
chromosomes
Chromosomes continue to move to the poles of the spindle
The telomeres at the ends of the chromosomes are the last
part of the chromatids to separate.
Each chromatid is pulled by its own centromere as the
kinetochore fibers shorten.
Ends when the chromosomes stop moving.
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Chromosomes spread out and spindles break apart
Nuclear envelop re-forms around each cluster of
chromosomes
Nucleolus becomes visible in each daughter cell
Mitosis is complete because the nucleus has divided, but the
cell has not divided yet
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The division of the cytoplasm
In animal cells, the cell membrane pinches
inward separating the cell into two equal parts
In plant cells, a cell plate forms in between the
two nuclei, separates the membrane and forms
a cell wall
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase