Staining cheek cells Materials: Toothpicks or cotton swabs Microscope slides and coverslips Surgical gloves Iodine (available from your local pharmacy) Eye dropper Light microscopes Plenty of paper towel!

Method Take the blunt end of a toothpick or a cotton swab and brush the inside of your cheek to pick up some cells Wipe the toothpick or swab on a microscope slide Wear gloves to handle iodine and cover surfaces – iodine can stain skin and clothing Using the eye dropper, carefully add a small drop of iodine onto the smear of cells Drop a coverslip on top of the iodine drop Use tissue or paper towel to wipe any excess iodine from the slide Starting at low magnification, use the microscope to look at your cheek cells Switch to a higher magnification What can you see? If you have cells from bacteria, yeast or plants, compare these with your cheek cells. What are the similarities? What are the differences?