Plant vs. Animal Cell Structures
Purpose:
· To observe animal cell structures which are not visible with the light microscope
· To observe plant cells
· To compare structures seen in plant and animal cells
Materials: Microviewer, slide and booklet, slide, cover slip, iodine, onion, elodea
Procedure:
Part I. Elodea Cells
1. Obtain a microscope, plug it in, and put the low power objective into place.
2. Prepare a wet mount slide of an elodea leaf. Focus it under low power, then move it to high power.
3. In number 1 of your data sheet, draw what you see. Be sure to label the cell wall, the cell membrane, and the chloroplasts.
4. Throw out the leaf, and rinse your cover slip and slide. You may reuse them for the next part.
Part II. Onion Cells
1. Remove a very thin layer of skin from an onion provided by your teacher.
2. Put the onion on a slide, and make a wet mount slide.
3. Focus it under low power, then under high power.
4. In number 2 of your data sheet, draw what you see and label any cell structures seen.
5. Bring your onion slide up to the front of the room. Remove the cover slip, and add a drop of iodine to the onion. Put your cover slip back on. Be very careful with iodine--it can stain your clothes!!
6. Focus the onion slide under low power, then move it to high power.
7. In number 3 of your data sheet, draw what you see and label the cell structures seen.
8. Carefully clean the slide and cover slip. Throw out the onion skin. Place the slide and cover slip on the paper towel at the middle lab table to dry.
Part II. Animal cells
1. Use the microviewer to observe the structures of the animal cell which are not visible with the light microscope.
2. On your data sheet, for each slide specified, draw what you see, and label each structure. Refer to the reading that goes along with each slide to help in labeling your diagrams.
Data:
Part I.
1. Elodea leaf
Part II.
2. Onion with water only 3. Onion with iodine
Part III.
Slide 1: This slide shows many cells from a human oil gland. Draw one cell, and label the cell membrane, nucleus, and cytoplasm.
Slide 2: Draw and label the endoplasmic reticulum, ribosomes, mitochondrion, nucleus, and nucleolus.
Slide 4: Draw and label the golgi body and vacuole.
Slide 7: Draw and label the chromosomes.
Analysis questions: Refer to your notes on cell structures and the reading in the booklet to answer the following questions.
1. What cell structures were you able to see in the elodea cells?
2. What cell structures were you able to see in the onion cells with just water?
3. When the iodine was added to the onion, what cell structures became stained and became visible to you?
4. Why were chloroplasts visible in the elodea leaf, but not in the onion? What other parts of a plant would contain cells without chloroplasts?
5. What structure is controlling all of the activities that occur within the cell?
6. Why does the endoplasmic reticulum wind all around the cell? What is its job in the cell?
7. What important information is found on the chromosomes?
8. Once proteins are made on the ribosomes, they will travel to what structure to be processed and packaged?
9. If you were looking at a plant cell, how would you expect the vacuole to look in comparison to how it looks in the animal cell?
10. Why the difference between the vacuoles in the plant and animal cells?
11. What kinds of cells in your body would you expect to contain a lot of mitochondria? Why?
12. Whenever materials need to enter or leave the cell, through what structure(s) will they pass in an animal cell? In a plant cell?
13. What structure would you expect to see attached to the vacuole in the plant cell, responsible for the digestion of food products?