Transcript Ch 5 Mitosis Powerpoint

To help
organisms:
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We grow
because our
cells divide
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Fingernail growth slows due to
mitosis slowing down.
Stomach
lining cells: 2 days
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Platelets: 10 days
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Skin Cells: 20 days
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Red Blood Cells: 120 days
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Brain cells: 30-50 years
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Intestinal
lining cells: 3 days
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• DNA plus proteins is called chromatin.
chromatid
• Strand of protein that attaches to
The chromosome is called a fiber.
telomere
• One half of a duplicated
chromosome is a chromatid.
centromere
• Sister chromatids – chromosome
after it has made an exact copy.
Held together at the centromere.
• Telomeres protect DNA and do
not include genes.
• Before the first step of Mitosis
chromosomes make exact copies
telomere
of themselves.
Condensed, duplicated chromosome
chromosome
• The four stages of the cell cycle are gap 1,
synthesis, gap 2, and mitosis.
1) Gap 1 (G1): cell growth and
normal functions
2) DNA synthesis (S): copies
DNA
3) Gap 2 (G2): additional
growth
4) Mitosis (M): includes
division of the cell nucleus
(mitosis) and division of the
cell cytoplasm (cytokinesis)
• Mitosis occurs only if the cell is large enough and the DNA
undamaged.
Mitosis and cytokinesis produce two genetically
• Mitosis- the
identical daughter cells.
Parent cell
process of
making new
centrioles
body cells
• Interphase
prepares the cell
to divide.
spindle fibers
Inter=G1-S-G2
• During
centrosome
interphase, the
nucleus with
DNA is
DNA
duplicated.
•Prophase
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•Metaphase
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•Anaphase
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•Telophase
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Sister
Chromatids
Nuclear
Membrane
Shorten and
Thicken
Begins to
break down
Centrioles
Move apart
from one
another
Fibers
Form between
centrioles
Sister
Nuclear
Chromatids Membrane
Become
attached to the
fibers. Are
pulled to
middle of cell
Remains
dissolved
Centrioles
Move to
opposite ends
of cells
Fibers
Are stretched
between the
two ends of
cell
Sister
Nuclear
Chromatids Membrane
Pulled apart
by fibers.
Each
chromatid is
separate from
its “sister”
Remains
dissolved
Centrioles
Still at cell’s
poles;
Fibers
Pull each
chromatid
toward
opposite
ends of cell
Sister
Nuclear
Chromatids Membrane
Each end of cell
has a complete
set of
chromosomes.
Begins to reform
Cell
Membrane
Begins to pinch,
forming two new
cells
Fibers
Begin to
disappear
• Cytokinesis differs in animal and plant cells.
– In animal cells,
the membrane
pinches closed.
– In plant cells, a
cell plate forms.
The process is VERY SIMILAR in each type of cell.
There are only 2 differences:
1. Plant cells do not have centrioles
2. A cell wall is laid down at the end of the cell division.
Plant cell
Cell Wall
Chloroplasts
Animal Cell
Animal Cell
Plant cell
Prophase
Anaphase
Metaphase
Telophase
Animal Cell
Plant cell
Centrioles
are not
always
found in
plant cells.
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Life Cycle Animation
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Mitosis video - DS
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Signs of Aging:
Loss of Hair
Loss of Calcium
Wrinkles
Cell division is uncontrolled in cancer.
•Cancer cells form disorganized clumps
called tumors. They cause problems by
crowding normal cells.
•Benign tumors remain clustered and can be
removed.
•Malignant tumors metastasize, or break
away, and can form more tumors.
normal cell
cancer cell
bloodstream
• Cancer cells do not carry out necessary
functions and crowd out normal cells.
• Cancer cells come from normal cells with damage to
genes involved in cell-cycle regulation.
• Carcinogens are substances known to promote
cancer.
• Standard cancer treatments typically kill both cancerous
and healthy cells.
1._________________________
2._________________________
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3._________________________
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ORGANISM
CAT
DOG
CHIMPANZEE
EARTHWORM
GOLDFISH
CARROT
LETTUCE
ONION
CHICKEN
GUINEA PIG
HUMAN
MOSQUITO
PEA
PENICILLIN
CORN
FROG
“GUESSTIMATE”
ACTUAL CHROMOSOME
#
32
78
48
36
94
18
18
16
78
64
46
6
14
1-4
20
26
Stem cells are unique body cells.
• Stem cells have the ability to
Meaning: The cell
could become a
lung cell, or a skill
cell;… it is NOT
predetermined!
– divide and renew themselves
– remain undifferentiated in form
– develop into a variety of specialized cell types
• Stem cells are classified into three types.
– totipotent, or growing into any other cell type
– pluripotent, or growing into any cell type but a totipotent
cell
– multipotent, or growing into cells of a closely related cell
family
• Stem cells come from adults and embryos.
– Adult stem cells can be hard to isolate and
grow.
– The use of adult stem cells may prevent
transplant rejection.
– The use of embryonic
stem cells raises
ethical issues
– Embryonic stem cells
are pluripotent and
can be grown indefinitely
in culture.
First, an egg is fertilized by a sperm cell in a petri
dish. The egg divides, forming an inner cell
mass. These cells are then removed and grown
with nutrients. Scientists try to control how the
cells specialize by adding or removing certain
molecules.
• The use of stem cells offers many currently
realized and potential benefits.
– Stem cells are used to treat leukemia and lymphoma.
– Stem cells may cure disease or replace damaged
organs.
– Stem cells may revolutionize the drug development
process.
Stem cells
Ethical issue