Background Information:

One of the first scientists to look at cells under a microscope was an English scientist by the name of Robert Hooke. He viewed and described the appearance of cork under the microscope and decided to name the tiny box-like structures that he observed “cells” because they looked like the small chambers where monks lived.

By the early part of the 19th century, it was accepted that all living things are composed of cells. Cells come in a variety of shapes and sizes, and cells perform different functions. Although cells may appear outwardly different, they resemble each other because they share common structures. In this lab you will look at three types of cells (a yeast cell, an onion cell, and a human cheek cell) and see how they are similar and how they are different.

Yeast (Fungi) Cell Procedure:

1. Rinse and dry a flat glass slide.2. Place a drop of yeast on the slide. Place a cover slip over the yeast. 3. Using the staining technique demonstrated in class, stain the yeast with methylene blue.

4. Place the slide on the stage and view the slide under the low power. Once you have found an area with several good cells, switch to medium and high power. Remember to only use the fine adjustment to focus at high power.

5. Using an FOV paper, draw one or two yeast cells in detail on the highest power. Label the following: cell wall, cytoplasm, nucleus, nuclear membrane.

6. Insert a picture in the Data and Observations Section.

FUNGI, PLANTS, ANIMALS

Onion Cell Procedure:

1. Clean a depression slide and dry. 2. Place a drop of water on the slide. Take a piece of onion from the bowl. Obtain one layer of

epidermal tissue (as demonstrated in class). Place the layer of tissue on a slide. Place a cover-slip on the slide, slowly lowering it over the sample to avoid creating air bubbles. Using the staining technique demonstrated in class, stain the yeast with iodine.

3. Place the slide on the stage and view the slide under the low power. Once you have found an area with several good cells, switch to medium and high power. Remember to only use the fine adjustment on high power.

4. Using an FOV paper, draw one or two onion cells in detail on the highest power. Label the following: cell wall, cytoplasm, nucleus, nuclear membrane.

5. Insert a picture in the Data and Observations Section.6. Clean the slide and dry.

Cheek Cell Procedure:

1.Put a drop of methylene blue on a clean, flat slide.

2.Gently scrape the inside of your cheek with the flat side of a toothpick. Scrape lightly.

3.Stir the end of the toothpick into the stain and throw the toothpick away.

4.Place a cover-slip onto the slide.

5.Use low power to focus. Once you have found an area with several good cells, switch to medium and high power.

6.Draw one or two skin cells in detail on the highest power. Label the following: cell membrane, cytoplasm, nucleus, nuclear membrane.

7.Insert a picture in the Data and Observations Section.

8.Throw out the cover slip, clean, and return slide to the paper towel. Get a new coverslip.

Data and Observations

YEAST CELL

PLANT CELL

ANIMAL CELL

Analysis Questions- Answer the following questions in complete sentences and in red.

1. How does the shape of the onion cells differ from that of the cheek cells?

The shape of the onion cell differs from the cheek cell by the onion cell is a rectangle and the cheek cell is a circle.

2. Which cells seem to be arranged in a more regular pattern?

The onion cell seems to be like a regular pattern.

3. What structures were you able to see in all three types of cells?

The structures we were able to see in this lab was plant, animal and fungi.

4. Describe two similarities between plant and animal cells.

Two similarities between plant and animal cells are they both have cytoplasm and they are both microscopic.

5. Describe two differences between plant and animal cells.

One difference between plant and animal cells is that plant sells have a cell wall. Another difference is that plant cells make their own food

7. What evidence do you have that humans are made up of cells?The evidence I have that humans are made up of cells is I saw my own cells.

8. Google a picture of a nerve cell and a muscle cell. Do all the cells in your body look like your cheek cells? Why or Why Not??

No all cells in our body look like cheek cells because our cheek cells look like a little baseballs.

9. Both plant cells and animal cells contain mitochondrion and yet there were not visible in the

cells you viewed in this lab. Does this mean that these organelles are not found in cheek and onion cells? Why or why not? Explain your reasoning.

Nervecellce

Musclecell

NO it does not mean they are not found in cheek and onion cells it just means are microsopes cannot magnigy enough to see them .