Eukaryotic Cell Lab

Introduction
Using microscopes allows humans to see things they’ve otherwise would have never seen before, like cells. A cell is the basic unit of life. All living things are made of cells. All cells come from preexisting cells through a process called cellular division. There are two types of cells, eukaryotes and prokaryotes. Prokaryotes are very simple and small. They are unicellular and have no membrane bound organelles. Their DNA is found directly in the cytoplasm since they have no nucleus. Eukaryotes are much more complex and bigger. They have membrane bound organelles for specific functions. Some organelles inside eukaryotic cells include: the nucleus, the golgi apparatus, the mitochondria, the chloroplast, the endoplasmic reticulum
(ER), vacuoles, lysosomes, microfilaments, and microtubules. Their DNA is contained within a nucleus. They can be unicellular or multicellular. There are two types of eukaryotic cells, plant and animal cells. The main differences between the two are that plant cells have a cell wall, chloroplast, and are a more rectangularly shaped while animal cells on the other hand don’t have a cell wall, chloroplast, and are a more circularly shaped. The purpose of this lab was to compare the structures of plant and animal cells.

II. Materials
Glass slide (one for each lab)
Cover slip (one for each lab)
Scalpel
Toothpick
Iodine stain
Medicine dropper
Beaker of water
Microscope
Onion
Cheek
Onion cell
Cheek cell
Colored pencils
Paper
Pencil

III. Methods/Procedure

A.) The Cheek Cell
Before the student started the lab, the student walked to the side of the room and got a microscope. Then the student carefully and correctly carried the microscope back to the desk by having one hand wrapped around the arm of the microscope and the other hand placed under the base of the microscope. Once the student got the microscope to the desk, the student walked to the back of the room where the cheek section was set up. Once there, the student took a glass slide and used the medicine dropper and dropped a bead of water on the slide. Then, the student took a toothpick and carefully scraped the inside of the cheek. After that, the student twirled the side of the toothpick that touched the cheek in the drop of water. Then, the student used the medicine dropper and dropped a tiny amount of iodine in the water. Finally, the student put a coverslip on top of all of it and went back to the desk. When the student got back to the desk, the student examined the slide under low power. The student turned the revolving nosepiece so that the low power objective was above the slide. Then the student looked through the eyepiece. To see the cheek cells, the student turned the knob on the side of the microscope called the coarse adjustment knob. Once the student found the cheek cells, the student used the fine focus adjustment knob and focused the image so that the cells could be seen more clearly. Once the image was focused, the student got up and walked to the side of the room and got colored pencils. The student walked back to the desk with the colored pencils, sat down, and drew and colored the image of the cells shown on the microscope. Then, the student labeled any visible parts of the cell. After finished with that, the student moved the revolving nosepiece so that the slide was now under the high power objective. Then, the student only used the fine focus adjustment knob and looked for the cells. Once the student focused the image and saw the cells, the student used the colored pencils and drew and colored the image of the cells shown on the microscope. Then the student labeled any visible cell part. Once completed, the student took the slide out of the stage clips and off the microscope. The student then took the slide and walked to the front of the room. The student threw the whole slide in a bag on the teacher’s desk. Then, the student walked back to the desk, picked up the microscope, walked to the side of the room, and then put the microscope back on the cart. Once the microscope was put away, the student washed up and was completed with the cheek cell lab.

B.) The Onion Cell
Before the student started the lab, the student walked to the side of the room and got a microscope.
Then the student carefully and correctly carried the microscope back to the desk by having one hand wrapped around the arm of the microscope and the other hand placed under the base of the microscope. Once the student got the microscope to the desk, the student walked to the front of the room where the onion section was set up. Once the student got there, the student picked up an onion and peeled a rather thin piece of the skin from the inner surface of the onion. The student then picked up a scalpel and carefully cut a very thin and small piece off the onion skin. Once the student got the desired piece, the student prepared the slide. First, the student acquired a glass slide then the student put the thin piece of onion skin on the slide. The student made sure that the onion skin wasn’t folded over itself. After that, the student used the medicine dropper and dropped a small bead of water on top of the onion skin. Once the onion skin was covered the student used the medicine dropper and dropped the tiniest amount of iodine in the water directly on top of the onion skin. Finally, the student picked up a coverslip and placed it carefully on top of the onion skin. Once completed, the student walked back to the desk and put the slide on the microscope. The student then looked for the onion cells under low power. The student first used the coarse adjustment knob on the
microscope. Once the student found the cells, the student used the fine focus adjustment knob and focused the image of the cells. After the student found a good, clear image of the cell, the student got up, walked to the side of the room, and got colored pencils. The student then walked back to the desk, drew, and colored the onion cells that were shown on the microscope. Once the student drew and colored the rectangular shaped onion cells, the student labeled any cell parts visible. After the student completed that, the student went back to the microscope and tried to find the onion cells under high power. The student turned the revolving nosepiece from the low power objective to the high power objective and then only used the fine focus adjustment knob and found the cells. When the student found the cells, the student got the colored pencils, drew, and colored the cells shown on the microscope. The student then labeled any visible cell parts. Once finished, the student took the slide over to the side of the room where the sinks were. Then the student washed, and cleaned off the slide. The student then threw away the piece of onion skin, put the slide and coverslip back in the box, and went back to the desk. Then, the student picked up the microscope and walked to the side of the room where the cart was. The student put the microscope away on the cart and went back over to the sink. Lastly, the student washed up and was completed with the cheek cell lab.

IV.
Data
There were more cells in the field of view under the low power objective and as the magnification changed to high power, the number of cells in view decreased.
Under low power in the microscope, the cheek cells looked like very tiny, dark circular flakes. Under high power, the cheek cells got much bigger. A dark dot in the cell and a dark layer outlining the cell were now visible.
Under low power in the microscope, the onion cells looked like tiny, rectangular shapes. Almost like a brick wall. Some of the cells had very faint, dark dots in them. Under high power, the onion cells got much bigger. Inside the cells, there were dark dots, a dark outer layer outlining the cells, and a fainter, but still visible, inner layer also outlining the cell.
Also noticeable was that the onion cells were grouped together in a large group whereas the cheek cells were scattered about.
*see attached drawings* V.
Discussion
When the cheek cells were under low power, they looked very tiny because the objective wasn’t powerful enough to show all the details. Once the objective was change to high power the cell became more detailed and more of the parts could be seen. The dark dot in the cell was the nucleus, and the dark layer outlining the cell was the cell membrane. The nucleus contains nearly all of the cell’s DNA. It also stores the coded instructions for making proteins and other important molecules. The cell membrane separates the cell from its environment and regulates what enters and exits the cell. When the onion cells were viewed under the microscope on low power, they looked like bricks, tiny and rectangular. Once the objective was changed to the high power objective a dark dot, a dark outer layer outlining the cells, and a fainter inner layer outlining the cells became visible. The dark dot was the nucleus, the dark outer layer outlining the cell was the cell wall, and the fainter inner layer outlining the cell was the cell membrane. Since the onion cells had a cell wall, the conclusion can be that onion cells are plant cells. Since the cheek cell only had a cell membrane and no cell wall, the conclusion can be made that cheek cells are animal cells.
The student learned in the lab that animal cells don’t have a cell wall and the cell is shaped in an irregular circle because they have no cell wall. The student also learned that an animal cell’s nucleus is located in the middle of the cell. Another thing the student learned was why plant cells are shaped like rectangles. The student found out that because plant cells have a cell wall it gives them support and rigidity making them rectangular. The student also learned what some organelles looked like. The nucleus is a small circle shape, the cell wall is a rectangle, and the cell membrane can be circular if it’s in an animal cell, or rectangular if it’s in a plant cell.
In class, the student was learning about each organelle of the cell and what the function and purpose of it was. This lab relates to that by showing the student a real organelle and what it actually looks like in a real cell.
In this lab, iodine stain was used. Iodine stain was used because the stain enhances parts of the cell to make them easier to see. Along with the iodine, the objective on the microscope that provided a better view of both the onion and cheek cell was the high power objective. The high power objective gave a better view of the cells because it showed more details and a closer look at the cell. The onion cells were shaped kind of like rectangles whereas the cheek cells somewhat resembled circles. Since the onion cells were shaped like rectangles, they seemed to be arranged in a more regular pattern. Almost like a brick wall. While looking at the cells under the microscope, the visible cell parts included: the nucleus, the cell membrane, the cell wall, and the cytoplasm. The cheek is a eukaryotic cell. When the cheek cell was examined under the microscope, there was a nucleus present. A prokaryotic cell doesn’t have a nucleus, but a eukaryotic cell does. However, some of the cell parts were not visible. Both plant and animal cells contain mitochondria, but it wasn’t shown under the microscope. Even though it wasn’t visible, both the cells have it. To see the mitochondria, a higher powered microscope would be needed. If a higher powered microscope was used, an even closer look at the cell would take place. Along with the mitochondria not being seen, ribosomes and the golgi apparatus were also not visible, but should have been in the cheek cell.