OBJECTIVE: to Observe the Structure of a Plant Cell

LAB: ONION CELLS

OBJECTIVE: To observe the structure of a plant cell.

MATERIALS: onion skin, iodine, microscope, slide, cover slip.

PROCEDURE:

Remove a small piece of the inner surface of an onion skin.
Place the piece of onion skin on a slide.
Cover the piece of skin with a drop of iodine.
Place a cover slip over the onion skin.
Observe under low power; change to high power and observe the onion skin.
Draw the cells of the onion skin under low power and high power.
Label the parts of one cell.

CONCLUSION:

Can you see the cell walls?
Can you see the cytoplasm?
Can you see the nucleus?
Can you see the vacuoles?
What color does the iodine stain the cell parts?

INFORMATION TO USE IN THE LAB:

All plant cells contain a cell wall, but not all the cell walls are stiff. Some of the cell walls are very thin in some plants. The onion skin has cells that look like the drawing below. If you have trouble locating an onion cell, study the diagram of the onion cell very carefully then look in the microscope for a structure that looks very similar to this.

ONION CELL LAB CONCLUSION

Answer the questions on the back of your data sheet or on a separate sheet of notebook paper. Write your answers in complete sentences in the form of a paragraph.

What type of cell did you observe today?

What structures or organelles could you see?

What color does the iodine stain the cell parts?

What magnification gave you the best view of the onion cell? Explain your answer.

What was the most interesting observation you made today?

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