Page 8 - Focus PT3 2020 Science ( BI Version )

Science PT3 Chapter 2 Cell as the Basic Unit of Life

Eksperimen 2.1
Eksperimen 2.1
Activity 2.1
Aim: To prepare an animal cell slide and to examine animal cells
(human cheek cells). Form Form
Materials and apparatus: Methylene blue solution, distilled water,
toothpick, filter papers, glass slide, cover slip, light microscope, dropper, 1
mounting needle and forceps.

Procedure:
1. A drop of distilled water is placed on the centre of a clean slide.
2. The blunt end of a toothpick is used to gently scrape the inner Distilled
lining of the cheek. water Toothpick
3. The scrapings are placed in the middle of the water drop on the Cheek
scrapings
slide.
4. A cover slip is lowered slowly on the specimen using a mounting
needle to ensure that air bubbles are not trapped under the cover
slip. Mounting
5. A drop of methylene blue solution is placed on one edge of the Cover slip needle
cover slip and a piece of filter paper is placed on the other edge of
the cover slip. The filter paper will draw the methylene blue solution
across the slide to stain the cells.
6. Excess methylene solution is absorbed using another piece of filter
paper.
7. The slide is observed under the low power objective lens of the
light microscope, followed by the high power objective lens.
8. The structure of the cheek cells is drawn and labelled accordingly.
Observations: Methylene
blue solution Filter
paper
Cytoplasm Figure 2.5 Preparing the slide of
human cheek cells
Cell membrane
TIMSS Challenge 1
Nucleus
Why do we need to add a drop of
methylene blue solution onto the
cheek cells when preparing the
Figure 2.6 Human cheek cells slide of cheek cells?

Discussions:
1. Methylene blue solution stains the cheek cell, so that the
structure of the cell can be seen clearly. Common Error
2. Human cheek cells do not have a fixed shape. All living things
3. The structures of the human cheek cells as seen under the light contain cells.
microscope are the nucleus, cell membrane and cytoplasm. All living things are
made up of cells.
Conclusion:
An animal cell does not have a fixed shape, and has a nucleus, cell membrane and cytoplasm.

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