Onion Root Lab: Modeling the
Phases of the Cell Cycle
Mr. Martinez.
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The Cell Cycle
The Cell Cycle is the series of events that take place in a cell leading to its
division and duplication (replication).
The Cell Cycle has 3 Stages: Interphase, Mitosis, and Cytokinesis.
Mitosis is a type of cell division that results in two daughter cells each having
the same number and kind of chromosomes as the parent nucleus
Mitosis has 4 phases: Prophase, Metaphase, Anaphase, and Telophase
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Onion, a garden plant of the lily family, 
closely related to the leek, garlic, chive, and
shallot. The bulb of the onion plant, also
called onion, is widely used as a seasoning
and is eaten as a vegetable. Although onions
have little food value, they impart a desirable
flavor to stews, soups, hamburgers, and
other dishes.
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Mitosis in Root Tip
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In a growing plant root, the cells at the tip of
the root are constantly dividing to allow the
root to grow.
Because each cell divides independently of
the others, a root tip contains cells at
different stages of the cell cycle.
This makes a root tip an excellent tissue to
study the stages of cell division
Stages of mitosis in onion root tip cells
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Experiment
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Materials
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Prepared Onion Root Tip Slides
Microscope
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Observe your preparation under the low power (X10) of a
microscope
Search the slide to find cells in various stages of cell division,
once you have located cells in division, change to high power
(X40) & try to observe several stages of division.
Record the number of cells in each stage.
Record your data in the table
Calculate the percentage of cells in each phase and record in
the table
Mitotic index
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A measure for the proliferation status of a cell
population.
It is defined as the ratio between the number
of cells in mitosis and the total number of
cells.
Animation
Lab:
http://www.youtube.com/watch?v=mUBlZ1V
NReQ
Video
http://www.youtube.com/watch?v=djXhEJUld
Nc
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Interphase
Prophase
Metaphase
Anaphase
Telophase
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