Mr. Martinez.

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Onion Root Lab: Modeling the Phases of the Cell Cycle

The Cell Cycle

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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

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

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

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Stages of mitosis in onion root tip cells

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Experiment

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Materials

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

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Mitotic index

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.

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Animation

Lab: http://www.youtube.com/watch?v=mUBlZ1VNReQ

Video http://www.youtube.com/watch?v=djXhEJUldNc

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Interphase Prophase

Metaphase Anaphase

Telophase