EXPERIMENTAL INVESTIGATION 3.2 How can we look at plant cells?
Equipment Onion
Method Without stain
1. Cut an onion on a chopping board. Use a forceps to gently peel off a thin layer of cells from the inner surface of the onion.
SAFETY • Be careful when handling glass slides.
• Take care when using a knife.
2. Using a dropper, add a drop of water to the glass slide. Carefully place the thin layer of cells on the glass slide, ensuring the layer of cells doesn’t fold over.
3. Follow steps 3–10 from Experimental Investigation 3.1. With stain
1. Place a drop of water on a fresh glass slide and carefully place a new, thin layer of cells on the surface of the glass slide, ensuring the layer of cells doesn’t fold over.
2. Using a dropper, add a drop of iodine stain to the slide. Remove any excess stain using tissue paper. 3. Using a seeker, gently lower a cover slip onto the glass slide. 4. Follow steps 4–10 from Experimental Investigation 3.1.
1 Forceps Drop of water Onion Glass slide 3 Iodine Glass slide 4 Seeker Cover slip Glass slide :Fig. 3.10 Preparing a specimen of plant cells to view under a microscope j Go to page 4 of your Experimental Investigations Log to write up this investigation. ? 2 Knife Water Chopping board Forceps Dropper
Glass slide Cover slip
Seeker Microscope
Iodine stain Tissue paper
TEST TUBE
7. What organelles are present in a plant cell that are absent in an animal cell? 8. What stain is used in the animal cell investigation? 9. What stain is used in the plant cell investigation?