Look at onion skin cells
Look at the cells of the onion epidermis under low power.
What is their general shape?
If you did not know their origin, how could you tell they are plant cells?
Observe the cells under high power. What evidence is there that these are living cells?
Find a cell nucleus
Remove the slide from the microscope stage.
Place a drop of the stain (coloring) at one edge of the cover glass.
Draw it under the cover glass by touching a piece of paper towel to the opposite edge.
(CAUTION: Stains can cause permanent damage to clothes and laboratory surfaces. Handle carefully.)
Under low power look for a nucleus that is stained brown or blue.
What is its shape?
Switch to high power and look at the nucleus again.
Where is the nucleus located in the cell?
How can you tell that the cell has depth?
Look at the area between the nucleus and the edges of the cell. You will find a fine granular (grainlike) substance that has been stained lightly.
Does the substance fill the entire cell? Describe what it looks like. How might this substance be different in cells that have not been stained?
