Transcript Cell Growth Chapter 10 PPT

Chapter 10: Cell Growth and
Division
10-1 Cell Growth
10-2 Cell Division
10-3 Regulating the Cell Cycle
Chapter 10 Concept Map
Chromatin
Chromosomes
Gene
Interphase
Sister Chromatids
Cell Cycle
Centromere
pg. 244-249
Cyclin
Mitosis
Prophase
Centrioles
Metaphase
Spindle
Anaphase
Cell Plate
Cleavage Furrow
Cytokinesis
Telophase
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Chapter 10 Concept Map
pg. 250-252
Results of Mitosis
Tissue
Organ
Organ System
Cancer
Tumor
Types of Skin Cancer
Melanomas
Squamous Cell Carcinoma
Basal Cell Carcinoma
Malignant Melanoma
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Cell Growth
Cell size limitations
 Surface area to volume ratio: The volume
of a cell increases faster than its surface
area.
 Diffusion: becomes inefficient at moving
necessary materials in and out of cell when
volume is too big

DNA: makes certain proteins necessary to
all organelles. In a large cell without
enough DNA, these proteins are not
produced quickly enough.
 “Information crisis” –cell can’t meet all of its
needs
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Cell Division
Chromosomes: Condensed clumps of
DNA that are visible right before cell
division, they unwind soon after.

Tightly packed
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Chromosome Structure
(like a ball of yarn)
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Cell Division
The Cell Cycle:
The cycle of
growth and
division of a cell
(interphase and
mitosis).
See Figure 10-4,
pg. 245.
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Cell Division
Interphase: The growth period of a cell.
• 3 Parts:
• G1 : The cell grows in size and carries
on metabolism (excretion, energy
production, making proteins).
• S : DNA replicated in preparation for
cell division.
• G2 : Cell parts needed for cell division
are assembled.
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Cell Division
Mitosis: The phase of the cell cycle
when the cell begins division; NO
VARIATION



Occurs when cell size is at a maximum.
Occurs in every cell of your body.
Four distinct phases, or stages.
 Prophase
 Metaphase
 Anaphase
 Telophase
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Prophase
First and longest phase of mitosis
Chromosomes are visible (DNA
condenses)
Each half of a replicated chromosome is
called a sister chromatid.


They are exact copies of each other
They are connected by a centromere.
 Scientists are often able to identify
chromosomes by the location of the
centromere.
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Prophase
Nucleus and nucleolus dissolve

They become no longer visible within the
cell
By late prophase, centrioles migrate
toward opposite ends of the cell.

Centrioles: Structures made up of
microtubules that aid in separation of sister
chromatids.
 Spindle fibers: many microtubules branching
out from the centrioles. Created to pull apart
sister chromatids.

Plants just have spindle form without the help of
centrioles.
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Prophase
Spindle Fibers
Chromatid
One Chromosome
Centrioles
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Metaphase = middle
Metaphase: The centromeres on the
sister chromatids become attached to
the spindle fibers. The chromatids are
then lined up in the middle of the cell.

Each centromere has one spindle fiber on
either side (one for each chromatid).
 These fibers come from the centrioles.
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Metaphase
One spindle fiber for each chromatid
that makes up the chromosome
Metaphase in an Onion
All chromosome line up in the middle
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Anaphase = away, apart
Anaphase: the sister chromatids are
separated


The centromeres split and the sister
chromatids are pulled apart.
The chromatids are pulled by the spindle
fibers toward the centrioles at the poles of
the cell.
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Anaphase
Chromatids are pulled by spindles, and separate
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Anaphase in an Onion
Telophase
Telophase: Phase is characterized by
cleavage furrow, or cell beginning to split its
cytoplasm into two distinct daughter cells.
Chromatids are now far away from each
other.

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
Chromosomes begin to unwind
Spindle breaks down
Nucleolus reappears
Nuclear envelope forms again around
chromosomes
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Cytokinesis
Cytokinesis: Cytoplasm of cell divides.
Occurs after telophase.

In a plant cell, a cell plate is laid down to
separate the contents of the two cells.
Plasma membranes form inside these new cell
walls that have been created.
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Telophase leading into cytokinesis
Cell wall formation
Telophase into cytokinesis in
an Onion 20
I-P-M-A-T
Interphase
Prophase
Metaphase
Anaphase
Telophase
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Control of the Cell Cycle
A series of enzymes (cyclins, etc.)
monitor a cell’s progress from phase to
phase.


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Enzyme production is directed by genes
Too many or too few of these enzymes can
disrupt a normal cell cycle
Also, the wrong enzyme production can
disrupt the cell cycle
Cancer: a disrupted cell cycle; can result
in excessive cell division
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Control of the Cell Cycle
Causes of Cancer

Environmental factors
 Smoking

Breast, mouth, lung, pancreatic, liver, etc.
 Exposure to sunlight (UV Radiation)

Basal Cell, Malignant melanoma
 Diet

Genetic Factors
 Faulty genes
 Viral infections
Basal Cell Carcinoma
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http://dermis.multimedica.de/doia/image.asp?zugr=d&lang=e&cd=67&nr=61&diagnr=173922
Types of Skin Cancers
Basal Cell Carcinoma

Most common type of skin cancer affecting the
deepest layer of cells of the epidermis.
Squamous Cell Carcinoma

Second most common type of skin cancer.
Malignant Melanoma


Most dangerous type of skin cancer arising from
pigmented areas of the skin.
Incidents of this cancer have increased among
young people due to increased sun exposure.
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ABCDE of Melanoma:
http://www.skincancer.org/skin-cancer/melanoma/melanoma_2.html
asymmetry, border, color, diameter, evolving
Benign
Malignant
Symmetrical
Asymetrical
Borders are even
Borders are uneven
One shade
Two or more shades
Smaller than 1/4 inch
Larger than 1/4
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Control of the Cell Cycle
An interesting fact: Where you live is
also an important factor in cancer rates


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When you move to a different country,
your chances of getting different kinds of
cancer change to those in your new
country.
The possibility of your getting certain
cancers is no longer the same as it was in
your original country
Cancer Growth Website
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Cell Size Limitations Circle Map
Volume
increases
faster than
surface area:
Cell doubles
in size
Area
increases 4x
Volume
increase 8x
Surface area to volume
Cell Size
Limitations
Diffusion
Too slow to transport material
in a large cell (BIG volume)
DNA
Large
cells
without
enough
DNA
cannot
produce
proteins
fast
enough
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Control of the Cell Cycle Circle Map
Enzyme
production
directed by
genes.
Enzymes monitor the
progress of a cell from
phase to phase.
Disrupted
cell cycle
results in
cancer.
Control of
the Cell
Cycle
Too many or too
few disrupt cell
cycle
Wrong
enzyme
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Cell Cycle Tree Map
Cell Cycle
Mitosis
Interphase
Longest phase of the
cell cycle
Growth phase
Prophase
Carries out metabolism
1st phase
Chromosomes
Longest of mitosis
duplicated
Cell parts assembled Chromosomes visible
Nucleus/Nucleolus
for cell division
dissolve
Centrioles migrate to
opposite ends of the
cell
Sister chromatids
Metaphase
Anaphase
Chromatids
line up at the
equator
Attached to
the
centromere
Sister
chromatids
begin to
separate
Pulled by
spindle
fibers
Telophase
Chromatids at
opposite ends
Cleavage furrow
Cell plate
Two daughter
cells formed
Nucleus and
nuclear envelope
reappear
Cytokinesis
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Causes of Cancer Tree Map
Causes of Cancer
Environmental
Smoking
Sunlight
Diet
Genetic
Faulty genes
Viral infections
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Cell Cycle Flow Chart
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