3. Viewing Cheek Cells

Instructions (Part I): Each student should gently scrape the inside of their cheek with a clean toothpick to avoid discomfort. Transfer the cells by stirring the toothpick in a drop of methylene blue placed in the center of a clean microscope slide. This stain will highlight the cells’ nuclei and other internal structures, making them easier to observe. Place a cover slip over the sample. Refer to the video below for additional instructions. Apply the techniques demonstrated in the video to your provided Foldscope materials.

Instructions (Part II):  Observe the structure of their cheek cells, noting the cell membrane (outside), cytoplasm (inside), and nucleus (dark portion in the middle that contains the DNA). See image below as a reference: 

Instructions (Part III): Compare and contrast the cheek cells to the onion cells observed earlier. What differences do you notice in the shape of the cells, the thickness of the cell walls in onion cells versus the more flexible cell membranes in cheek cells, and the visibility of the nucleus in each type? Hypothesize a reason for these differences and share with your partner and/or group.

Instructions (Part IV):  Use the QR code provided below to upload an image of your cheek cells. Type your first name in the “Subject” area.