Cell Survey
Purpose: The purpose of this activity is for you to view a variety of cells and cell parts and begin to understand the similarities and differences between different cells and their parts.
Below you will make preparations of the following “things.” You can go in any order that you like. You can reuse the same slide and cover slip throughout the activity. Be sure to use lens paper only when cleaning slides and lenses. Make every effort possible to not get the microscope lenses wet.
In every cell you should be able to see the following: cell membrane, cell wall (not in animal cells), and cytoplasm. There are 10 items listed. You must do the “*” items. You must do at least one of the other ones. The others are pretty cool too, though.
*1. Cheek cells
Put a drop of water in the center of a clean slide. Gently scrape the inside of your cheek with the flat part of a toothpick. You’ll get plenty even if you cannot see them. Stir the water on the slide with the toothpick to mix the cells with the water. Add one drop of methylene blue. Wait one minute. Add a cover slip. Observe under the highest power possible. Draw what you see, note magnification, and label any parts that you can. Hope to see: nucleus and nucleolus
*2. Onion cells
Add one drop of water to the middle of a clean slide. Tear off a thin (one cell layer thick) piece of onion skin (as demonstrated) and place it in the water. Try to get the skin as flat as possible on the slide. Add one drop of safranin. Wait one minute. Add a cover slip. Observe under the highest power possible. Draw what you see, note magnification, and label any parts that you can. Hope to see: nucleus.
3. Elodea cells
Add one drop of water to the middle of a clean slide. Tear off one leaf (one cell layer thick) and place it in the water. Try to get the leaf as flat as possible on the slide. Add a cover slip. Observe under the highest power possible. Draw what you see, note magnification, and label any parts that you can. Hope to see: chloroplasts.
4. Tomato cells
Add one drop of water to the middle of a clean slide. Tear off a thin (one cell layer thick) piece of tomato skin (as demonstrated) and place it in the water. Try to get the skin as flat as possible on the slide. Add a cover slip. Observe under the highest power possible. Draw what you see, note magnification, and label any parts that you can. Hope to see: chromoplasts.
*5. Prokaryote cells
See the set up demo under the oil immersion microscope. The bacteria will appear as geometric shapes (round = coccus and rod = bacillus). They are either pink (Gram -) or purple (Gram +). You may see chains (strepto-), clusters (staphlo-), pairs (diplo-) or singles. For example if you see a chain of round bacteria you would be looking at “streptococcus” – like bacteria that causes strep throat. Note that these are slides made by Ms. Purdy from a microbiology lab. The patient samples are anonymous. Hope to see bacteria in different arrangements and colors.
5a. Prokaryotes cells
Add one drop of water to a clean slide. Add a small drop of yogurt to the water. Swirl the water and the yogurt with a toothpick. Add one drop of safranin. Wait one minute. Add a coverslip. Observe under the highest power possible. Draw what you see, note magnification, and label any parts that you can. Hope to see bacteria.
6. Potato cells
Add a drop of water to clean slide. Remove a tiny piece of potato and place it in the water. Add a cover slip over the piece and then squash it (as demonstrated). Remove the cover slip and add one drop of iodine. Wait one minute and replace the cover slip. Observe under the highest power possible. Draw what you see, note magnification, and label any parts that you can. Hope to see: Amyloplasts
7. Avocado cells
Add a drop of water to clean slide. Remove a tiny piece of avocado and place it in the water. Add a cover slip over the piece and then squash it (as demonstrated). Observe under the highest power possible. Draw what you see, note magnification, and label any parts that you can. Hope to see: Elaioplasts
*8. and 9. Prepared slides
View at least two prepared slides. Draw what you see and label any parts that you can.
10. Pond critters/Nematodes/Aquarium critters
Obtain one/two drop(s) of one of the above. Take a drop where the substrate meets the water. Look in the beaker to see if see any moving critters and try to capture them with your pipette. Be careful not to squirt bubbles into the beaker since it causes a title wave to the critters. Use the depression slides as directed. Use no stain and no cover slips. See the pond critter pictures for identification. Draw what you see, note magnification, and label any parts that you can.
Cell Survey Drawings 3pts. each
Name:
1. Cheek cells: magnification ______Notes:
2. Onion cells: magnification _____ Notes:
3. Prokaryote cells: magnification _____ Notes:
4. Prepared slides: magnification _____ Notes:
5. ______magnification _____ Notes: