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Virtual Lab – Microscopy – Animal Cells (Human Epidermal Cells) Animal cells are another example of a eukaryotic cell. They are surrounded by a selectively permeable membrane called a plasma membrane and they have a large nucleus that contains genetic material. Some animal cells are motile with cilia or flagella. The animal cells that we will be observing in this simulation come from the inside of our mouths (cheek epidermal cells). Cheek cells are squamous epithelial cells that line the inside of our oral cavity. They protect the cells underneath and secrete mucin to lubricate the oral cavity. Cheek cells divide quickly and they shed easily. Every time you eat, you are swallowing thousands of your own cheek cells. In this activity, we will observe cheek cells from the inside of our mouths under the light microscope. Since most cellular structures are colorless, it is important to treat many kinds of cells with some kind of stain before observing them with a light microscope. The color contrast the stain provides allows better observation of cellular detail and activity.

Virtual Lab – Microscopy – Plant Cells (Onion Epidermal Cells) Many organelles are not visible in onion cell images primarily due to the following reasons: Size and Resolution Cell Wall and Structure Staining Techniques

Virtual Lab – Microscopy – Plant Cells (Onion Epidermal Cells) The general shape of an onion cell is typically circular or spherical.

Virtual Lab – Microscopy – Plant Cells (Onion Epidermal Cells) Why must the specimen be centered before switching to a higher magnification?

Virtual Lab – Microscopy – Animal Cells (Human Epidermal Cells) At 40x magnification, the structures of the cheek cells that are typically visible include the cell membrane, proteins, and amino acids.

Virtual Lab – Microscopy – Plant Cells (Onion Epidermal Cells) What is the most prominent organelle that you see in the onion cell images?

Virtual Lab – Operation of Bright Field Microscope How do you calculate total magnification for a compound light microscope?

Virtual Lab – Operation of Bright Field Microscope When using the 100X objective lens, a drop of water is needed on the specimen slide. 

Virtual Lab – Label the Parts and Describe the Function of the Parts of the Microscope Directions: Use the word bank to complete the table below by matching each microscope part to its corresponding number.  Mechanical Stage Rotating Nosepiece Fine Focus Knob Objective lens Coarse Focus Knob Oculars Condenser Stage adjustment knobs Iris Diaphragm Light source       1. [part1] 6. [part6] 2. [part2] 7. [part7] 3. [part3] 8. [part8] 4. [part4] 9. [part9] 5. [part5] 10. [part10]          

Virtual Lab – Microscopy – Plant Cells (Onion Epidermal Cells) What did you notice happened with the microscope image as you increased magnification?