Laboratory work 2: studying plant and animal cells under the microscope
The work is done under the teacher’s guidance. Place a thin piece of red onion skin (peeling the layer off is shown by the teacher or an adult) in a drop of water on a slide, cover it with a cover slip and view it first on low and then on high power. You see polygonal cells, a thick wall, a coloured vacuole and a nucleus. For cheek cells use only your own clean, single-use stick or cotton swab to lightly rub the inside of the cheek and smear the sample into a drop of iodine solution on a slide; the iodine solution (supplied by the teacher) must not get into the mouth, and must not be swallowed. An animal cell is flat, of irregular shape, with no wall, and a granular cytoplasm and nucleus are visible. Afterwards dispose of used material as the teacher instructs and wash your hands with soap; never work with another student’s sample.
“Detective”. The teacher shows two pictures (onion and cheek cells); groups prove which is the plant cell using at least three features.