Preparation of temporary mounts of
animal cells and tissues
Results: (7 marks)
Make a labelled high power drawing 高倍標註圖of the cornea cells of ox eye in the space below.
Discussion: (9 marks)
1 Why is it necessary to cover the slide with a cover slip in the observation under the microscope? (2 marks)
Any TWO of the following (1 + 1 = 2):
To flatten the samples;
To focus and observe the samples more easily;
To avoid contamination of the objective by the samples or the liquid on the slide;
To prevent evaporation of water from the samples leading to drying up of the samples;
To prevent the samples from being damaged.
2 What cellular structures can be observed under the light microscope? (3 marks)
Cell membrane, nucleus and cytoplasm (3)
3 What is the general position of the nucleus in animal cell? (1 marks)
At any positions of the cells (1)
4 Can you find vacuoles in these animal cells? (1marks)
No / Only minute vacuoles can be found (1)
5 Describe and explain if there is any change if methylene blue was not added before observation. (2 marks)
The image would become blurred / The nucleus or the cytoplasm could not be observed (1).
This is because the cellular structures are not stained (1).
Preparation of temporary mounts of plant cells and tissues
Results: (8 marks)
Make a labelled high power drawing of the plant cells of onion cells in the space below.
Discussion: (11 marks)
1 What cellular structures can be observed under light microscope? (4 marks)
Cell wall, cell membrane, nucleus, cytoplasm, (granules) (1@ X 4 = 4)
2 What is the general position of the nucleus in plant cell? (1 mark)
At the peripheral region of the cell (1).
3 Are all cells under observation green in colour? Why? (2 marks)
No (1). This is because not all plant cells have chloroplasts or chlorophyll / only plant cells with chloroplasts are green under observation (1).
4 State TWO similarities and differences between animal cells and plant cells. (4 marks)
Any TWO similarities and differences (2@ X 2):
Similarities: Both of them have cell membrane, cytoplasm and nucleus (2).
Differences: Plant cells have cell wall and larger vacuole but animal cells do not (2).