Page 24 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six
P. 24
Biology for Secondary Schools
Safety precaution 6. Gently cover the specimen with
Take precautions when using a coverslip making sure that no
sharp objects, such as knife and air bubbles are trapped inside, as
razor blade.
shown in Figure 2.16.
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2. Obtain a fresh leaf from one of
the quarters.
3. Use a pair of forceps to peel a
thin layer from a leaf, as shown
in Figure 2.14.
Figure 2.16: Covering the specimen
using the coverslip
7. Dry any excess water from the
sides of the coverslip using a
blotting paper.
Figure 2.14: Peeling a thin layer from an 8. Mount the slide on the stage of
onion leaf the light microscope. Hold it in
4. Trim the thin layer to place with the stage clips.
approximately 5 mm x 5 mm 9. Observe the specimen under the
using the scalpel or knife. low power objective lens, then
5. Put a drop of water on the
microscope slide. Place the observe under the medium power
trimmed thin layer of onion leaf objective lens.
in the drop of water using a glass 10. Remove the specimen from the
rod or a mounting needle, as microscope stage. Remove the
shown in Figure 2.15. specimen from the slide and put
a new specimen. Put a drop of
iodine on the specimen. Repeat
the procedures. Iodine makes
the specimen clear. Use blotting
paper to eliminate any excess
Figure 2.15: Placing the thin layer of iodine.
onion leaf on the slide
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