Lab Summary 1. “Plants and animals obtain food in different ways.” What microscopic evidence did you see to support that statement? Plant cells have chloroplasts and organelle that can produce food. Animals do not.
2. Did the iodine solution aid in your observation of onion cells? Why do biologists use stains to study cells? Yes, the cytoplasm and the nucleus were much easier to see. Stains allow parts of the cell to be seen more clearly.
3. What microscopic structure shows that the onion cell is a plant cell? The cell wall
4. What structures can be seen in an unstained onion cell? The cell wall
5. What structures can be seen in a stained onion cell? The cell wall, cytoplasm and nucleus, (maybe the cell membrane)
6. In what ways are Elodea cells different from onion cells? What organelle does Elodea have that the onion does not? Why might this be so? The Elodea has chloroplasts and the onion cells did not. The onion cells that we were looking at are found below ground where the sun doesn’t shine; therefore, chloroplasts are of no use to them. If I had given you the leafy part of the onion, you would have seen chloroplasts.
7. The plasma membranes of plant cells are difficult to see. Why? They are so thin and since they lie next to the cell wall they are hard to see.
8. In what ways are cheek cells different from plant cells? What structures are not found in the cheek cells? Cheek cells are irregular in shape and much smaller. They do not have cell walls, chloroplasts, or a large vacuoles.
