Prentice Hall
Biology
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10-2 Cell Division
In eukaryotes, cell division occurs
in two major stages.
The first stage, division of the cell
nucleus, is called mitosis.
The second stage, division of the
cell cytoplasm, is called
cytokinesis.
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10-2 Cell Division
Chromosomes
Chromosomes
Genetic information is passed
from one generation to the next
on chromosomes.
Before cell division, each
chromosome is duplicated, or
copied.
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10-2 Cell Division
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10-2 Cell Division
Chromosomes
Each chromosome
consists of two
identical “sister”
chromatids.
Each pair of
chromatids is
attached at an area
called the
centromere.
Sister chromatids
Centromere
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10-2 Cell Division
Chromosomes
When the cell divides, the
chromatids separate.
Each new cell gets one
chromatid.
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10-2 Cell Division
The Cell Cycle
The cell cycle is the series of events
that cells go through as they grow and
divide.
Interphase is the period of growth that
occurs between cell divisions.
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10-2 Cell Division
The Cell Cycle
During the cell cycle:
• a cell grows
• prepares for division
• divides to form two daughter
cells, each of which begins the
cycle again
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10-2 Cell Division
The Cell Cycle
The cell cycle consists of four phases:
• G1 (First Gap Phase)
• S Phase
• G2 (Second Gap Phase)
• M Phase
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10-2 Cell Division
Events of the Cell Cycle
During the S phase,
• chromosomes are replicated
• DNA synthesis takes place
Once a cell enters the S phase, it
usually completes the rest of the cell
cycle.
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10-2 Cell Division
Events of the Cell Cycle
The G2 Phase (Second Gap Phase)
• organelles and molecules required
for cell division are produced
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10-2 Cell Division
Events of the Cell Cycle
During G1, the cell
•increases in size
•synthesizes new proteins and
organelles
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10-2 Cell Division
Events of the Cell Cycle
Cell Cycle
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10-2 Cell Division
Mitosis
Biologists divide the
events of mitosis into four
phases:
•Prophase
•Metaphase
•Anaphase
•Telophase
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10-2 Cell Division
Mitosis
Mitosis
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10-2 Cell Division
Mitosis
Section 10-2
Spindle
forming
Prophase
Prophase
Chromosomes
(paired
chromatids)
Centromere
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10-2 Cell Division
Mitosis
Spindle
forming
Prophase
first and longest
phase.
The centrioles are
formed.
Centromere
Chromosomes
(paired
chromatids)
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10-2 Cell Division
Mitosis
Spindle
forming
A spindle
forms, strands
of proteins that
helps separate
the
chromosomes.
Centromere
Chromosomes
(paired
chromatids)
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10-2 Cell Division
Mitosis
Metaphase
Centriole
Spindle
Centriole
Metaphase
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10-2 Cell Division
Mitosis
Centriole
Metaphase
• chromosomes
line up across the
center of the cell.
•spindle connects
to the centromere
Spindle
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10-2 Cell Division
Mitosis
Anaphase
Individual
chromosomes
Anaphase
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10-2 Cell Division
Anaphase
Mitosis
Individual
chromosomes
The sister
chromatids
separate into
individual
chromosomes.
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10-2 Cell Division
Mitosis
Telophase
Nuclear
envelope
reforming
Telophase
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10-2 Cell Division
Mitosis
Telophase
Chromosomes
gather at
opposite ends
of the cell and
lose their
distinct shape.
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10-2 Cell Division
Mitosis
A new nuclear
envelope forms
around each cluster
of chromosomes.
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10-2 Cell Division
Cytokinesis
Cytokinesis
Cytokinesis
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10-2 Cell Division
Cytokinesis
cytokinesis
• cytoplasm pinches
in half.
Each daughter cell
has an identical set
of duplicate
chromosomes.
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10-2 Cell Division
Cytokinesis
In plants, a structure known as the cell plate forms
midway between the divided nuclei.
Cell plate
Cell wall
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10-2 Cell Division
Cytokinesis
.
A cell wall then begins to appear
in the cell plate.
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