Transcript Cell Growth and Reproduction

Cell Growth and
Reproduction:
MITOSIS
Objectives:
A.
List the purpose of cell division
B.
Diagram the cell cycle
C.
Explain the structure and purpose of chromosomes
D.
Sketch and explain the steps of mitosis
E.
Describe on a basic cellular level the cause of cancer
If we are all made up of cells….
How do little elephants grow up to be BIG
elephants?
A.
List the purpose of cell division
How is it possible for animals to shed
their skin?
A.
List the purpose of cell division
Cells Divide and
multiply constantly!!
A.
List the purpose of cell division
Why do cells divide?
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Growth
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Repair
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Replacement
•We shed old skin
cells constantly
A.
List the purpose of cell division
Why do cells divide?
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A.
Cells divide CONSTANTLY!!
As organisms grow and change, worn out
tissues are repaired or replaced by newly
produced cells.
List the purpose of cell division
The Cell Cycle
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The cell cycle is the sequence of growth and
division of a cell.
The growth period is called INTERPHASE.
During interphase the cell:
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Grows
Carries on basic life processes
Makes copies of DNA for cell division
The division period is called MITOSIS.
B. Diagram the cell cycle
B. Diagram the cell cycle
The Cell Cycle – A quick Review
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Interphase
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G1—Cell is growing
S – DNA replicates
G2 – Prepares for division
Mitosis
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Prophase
Metaphase
Anaphase
Telophase
B. Diagram the cell cycle
Chromosomes
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Chromosomes are cell structures that carry
genetic material. They contain DNA.
Chromosomes are always present in cells.
The genetic material is passed from
generation to generation.
C. Explain the structure and purpose of chromosomes
The structure of chromosomes
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During most of the cells life, chromosomes exist as
chromatin, which are strands of DNA.
In what cell organelle is this found? THE
NUCLEUS!
As the cell begins to divide the chromatin coils
forming short, thick chromosomes.
Each chromosome is made up of two halves called
sister chromatids.
They are exact copies of each other.
The sister chromatids are held together by a
centromere.
C. Explain the structure and purpose of chromosomes
The Structure of Chromosomes
Double
Chromosome
(sister
chromatids)
centromere
chromosome
C. Explain the structure and purpose of chromosomes
Mitosis
http://www.cellsalive.com/mitosis.htm
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase & Cytokinesis
D. Sketch and explain the steps of mitosis
Interphase
Stage of GROWTH before mitosis begins
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Chromosomes are copied (# doubles)
Chromosome copies are called Sister
Chromatids
Nucleus
CELL
MEMBRANE
Cytoplasm
D. Sketch and explain the steps of mitosis
Interphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
D. Sketch and explain the steps of mitosis
Prophase
1st step in Mitosis
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Centrioles (or poles) appear and begin to move to
opposite end of the cell.
Spindle fibers form between the poles.
Centrioles
Sister chromatids
Spindle fibers
D. Sketch and explain the steps of mitosis
Prophase
Animal Cell
Plant Cell
Spindle fibers
Centrioles
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
D. Sketch and explain the steps of mitosis
Metaphase
2nd step in Mitosis
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Chromatids (or pairs of chromosomes) attach to
the spindle fibers.
Chromosomes line up in the MIDDLE
Metaphase=Middle
Centrioles
Spindle fibers
D. Sketch and explain the steps of mitosis
Metaphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
D. Sketch and explain the steps of mitosis
Anaphase
3rd step in Mitosis
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Chromatids (or pairs of chromosomes) separate
and begin to move to opposite ends of the cell.
Anaphase = Apart
Centrioles
Spindle fibers
D. Sketch and explain the steps of mitosis
Anaphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
D. Sketch and explain the steps of mitosis
Telophase
4th step in Mitosis
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Two new nuclei form.
Mitosis ends.
Nuclei
Chromatin
D. Sketch and explain the steps of mitosis
Nuclei
Telophase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
D. Sketch and explain the steps of mitosis
Telophase completes with:
Cytokinesis
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Cell membrane pinches together to create two
daughter cells – each with its own nucleus with
identical chromosomes.
D. Sketch and explain the steps of mitosis
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
D. Sketch and explain the steps of mitosis
Plant Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
D. Sketch and explain the steps of mitosis
Cell Cycle
27
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http://www.cellsalive.com/mitosis.htm
What are the leading causes of death
in the United States?
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1- Heart Disease
2- Cancer
3- Stroke
4- Accidents, Alzheimer’s, Diabetes
E. Describe on a basic cellular level the cause of cancer
What is Cancer?
Cancer:
Uncontrolled
cell growth creating a
malignant tumor
AKA: Mitosis out of control
Mutation
 Occasionally
a cell is mutated
 The mutated cell will continue
to divide and multiply into what
could be cancer.
Mutation
 What
INCREASES chances of
cell mutation?
Radiation
 Carcinogens (drugs, nicotine,
alcohol, etc)
 UV rays
 etc
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Bell Quiz
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1. What is the process called when cells
divide?
2. Why do cells need to divide?
3. Name the stages of Mitosis in ORDER
4. What is cytokinesis? Which stage of
mitosis does it occur during?
5. What is the similarity of a cell from it’s
daughter cell?
Bell Quiz
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Draw & Label the process of mitosis
The first phase – Prophase
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During prophase the long and stringy
chromatin coils up to visible chromosomes.
The nuclear membrane disappears.
Centrioles move to opposite ends of the cell
and the spindle begins to form between them.
D. Sketch and explain the steps of mitosis
The second phase – Metaphase
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Metaphase is when the chromosomes
become attached to the spindle fibers.
They line up in the middle of the cell.
The third phase – Anaphase
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During anaphase the centromeres split
apart and chromatid pairs from each
chromosome split apart from each other.
Each chromatid is now a separate
chromosome.
The fourth phase – Telophase
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Telophase begins as the chromatids
reach the opposite ends of the cell.
The cytoplasm divides, the nucleolus
and nucleus reappear and the
chromosomes begin to uncoil.
The cell is now ready to start the cell cycle
again with interphase.
The division of the cytoplasm
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Towards the end of telophase the cytoplasm
divides. (CYTOKINESIS)
This happens differently in animal and plant
cells.
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In animal cells the plasma membrane pinches in.
In plant cells a cell plate forms across the cell’s
equator.
DIVISION IS NOW COMPLETE!