Transcript Mitosis - Spanish Point Biology

Cell Cycle
• The cell cycle describes the cell’s activities
in the state of
• non-division (interphase)
• and division (mitosis).
(cells can only come from cells)
Interphase
• Cell builds up store of energy
• Organelles are duplicated
• DNA replicates just before mitosis starts
(individual chromosomes not visible)
The four phases of mitosis are
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prophase
metaphase
anaphase
telophase
Prophase
• The chromosomes become visible.
(short, thick and duplicated).
• Centrioles move to opposite poles.
• Spindle fibres start to form.
• Nuclear membrane dissolves.
Middle
Metaphase
• Chromosomes line up along the equator
• Chromosomes connected
– from centromere
– to both centrioles
– by the spindle fibres
Apart
Anaphase
• Centromere splits
• Spindle fibres contract
• Chromosomes separate and are pulled to
opposite poles
Two
Telophase
• Nuclear membrane re-forms around each
set of chromosomes
• Chromosomes no longer visible now
called chromatin.
• Spindle dissolves.
Cytokinesis
• Division of cytoplasm
• Cleavage furrow formation in animal cells
• Cell plate formation in plant cells.
• In Unicellular Organisms
=Reproduction
• In Multicellular Organisms
=Growth
• Produces new cells, not new individuals
• Responsible for growth & renewal and repair of cells
Mitosis
•Type of cell division
•2 identical daughter cells produced
•No change in chromosome number
•Occurs in somatic (body) cells
•No variation
Cancer
• Uncontrolled cell division -cells divide too
fast and too often
• No control of mitosis
• Cells don’t stop dividing when they should
• (usually when in contact with other cells)
• Caused by – uv radiation, cigarette smoke
Arrange in
correct
order
Do I know….
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the stage when the cell is not dividing
the 4 stages of mitosis
the events of prophase
the events of metaphase
the events of anaphase
the events of telophase
Do I know….
• how the cytoplasm divides in animal cells
• how the cytoplasm divides in plant cells
• the function of mitosis in single celled
organisms
• the functions of mitosis in multi-celled
organisms
Next
haploid/diploid
meiosis (descrp & diffs and functions)
chromosome
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Contemporary Issues & Technology
Tissue culture:
Explanation: a technique in which individual cells are grown and divide in a bath of
sterile nutritive fluid which
often contains hormones and growth substances.
Reference to any two applications: cancer research, plant breeding, routine analysis
of chromosome karyotypes.