Microscopes & cells Objectives:

7. coarse focusing knob_______________________________________________________________8. fine focusing knob________________________________________________________________

Using stainsStains are used to improve contrast. This improves viewing with a microscope.The next sections use two different stains. The first stain, methylene blue, stainsmembranes. The second stain, iodine, stains starch.Methylene blue and cheek cells Gently scrape the inside of your cheek with the tip of a toothpick andsmear it on your slide. Add a small drop of methylene blue. Add a cover slip. Start on low power and progress up to high power Focus on a single cell. Try to identify the plasma membrane, cytoplasm, and nucleus. Notice that animal cells do not have acell wall. Sketch a single cell and label organelles. Find a group of cells clumped together. Sketch this clump of cells.Single cheek cell under high powerwith organelles labelledClump of cheek cells under high power26. Describe the spatial relationship between individual cells in thisgroup of cheek cells: side by side, or overlapping? __________________27. What might be the advantage to how cheek cells are in relationship to eachother?______________________________________________________________28. Describe the spatial relationship between individual cells in theElodea leaf:______________________________________________________________