Page 15 - Innovator's Science-8

• Place the peel in a petri dish containing a few drops of safranin (red-coloured
stain) for 30 seconds. This will give a pinkish colour to the cells and help us see
them clearly.

• With the help of a thin brush transfer the onion peel to another
petri dish containing water. Rinse the peel and remove extra
stain.
• Now, carefully place the stained onion peel on the glass slide
using a thin brush, ensuring it does not break or fold.
• Put a drop of glycerin over the onion peel on the slide. The a. Removing
onion peel from an
glycerin will prevent drying of the cells and improve clarity for onion bulb
be er visualisa on of cells.
One drop of
• Slowly place a coverslip over the safranin Glycerin
peel using a needle, such that no Onion peel
air bubbles get trapped.
• Use blo ng paper to gently wipe 1. 2. 3. 4.
off any extra glycerin around the Microscope
Cover slip
edges of the coverslip.
45°
• View the slide under a microscope
or a fold scope. 5. 6.
• What similari es do you find?
Conclusion: You will observe nearly rectangular structures under the microscope.
These are the cells of the onion peel, which are closely arranged without any space
between them. Try to observe the peels of the leaves of different plants around you.
You will find that all plants are made up of cells. What do you think the body of an
animal is made of?

Now let us observe animal cells and see how they differ from plant
Cell wall
Cell
membrane cells.
Nucleus
Cytoplasm This activity is about making a temporary slide to observe cheek cells
(a) under a microscope. First, you need to rinse your mouth with clean
water so that there are fewer food particles. Then, using the blunt
end of a toothpick, gently scrape the inside of your cheek to collect
some cells. Place this material in a drop of water on a clean glass slide
and spread it evenly. Next, add a drop of methylene blue stain, which
(b)
(a) Structure of onion peel makes the otherwise transparent cells
under the microscope
(b) A wall made of brick visible by giving them a blue color. After Cell membrane
about a minute, add a drop of glycerin to Cytoplasm
prevent the cells from drying out. Carefully

place a coverslip over the drop and gently
Nucleus
remove any extra glycerin from the slide's
edges using blotting paper. Finally, observe the Mount of human cheek cells

15
Science-8