- Appreciate the contribution of the technological development of the microscope to the discovery of cells.
- Prepare temporary mounts of specimens for examination, and make observations and drawings under a light microscope.
- Identify cell organelles as seen under light and electron microscopes.
Why cell can be discovered 🤔 ❓ ❔
- Invention of microscope make the discovery of cell become achievable.
- The scientist who first discovered cell is Robert Hooke. 👨🏻🔬
That's the microscope Robert Hooke utilised to discover cell 👇🏻
How to make observation under light microscope 😲❓ ❔
1. Preparation of temporary mounts
- Sectioning, staining and mounting are the process for preparing a temporary mounts.
- 1️⃣ A drop of water is placed in the centre of the slide.
- 2️⃣ Position the sample on the drop of water.
- 3️⃣ Place the cover slip slowly on top of the sample to avoid the occurrence of air bubbles.
- 4️⃣ Excessive water is removed from the slid with a paper towel.
- 🔺 Staining the sample with iodine, methylene blue and crystal violet can achieve a clearer observation.
2. Observation under light microscope
- 1️⃣ Moving the stage down to the lowest position.
- 2️⃣ Place the slide onto the stage and hold in position with the clip.
- 3️⃣ Select the lens with the lowest magnification.
- 4️⃣ Turing of coarse adjustment knob till you can see the cells.
- 5️⃣ Turing of fine adjustment knob till you can see the cells clearly.
- 6️⃣ Using lens with higher magnification with see the cells with larger magnification that more details of the cells can be observed .
3. Drawing of the cell under observation
In HKDSE Biology examination, you have to know how to draw the organelle you observed under light microscope with label ❗️ ❕
👆🏻This is the drawing of animal cell with labels.
👆🏻This is the drawing of plant cell with labels.
Identification of organelles under light microscope and electron microscope 💡
In HKDSE Biology examination, you will be given photo as shown and you have to identify the organelle one by one ❗️ ❕
👆🏻These are the image of animal cell and plant cell under electron microscope.
That's the end of this topic 👏🏻
R eferences
- Rhoads, D. (2020, March 18). History of Cell Biology. Retrieved from https://bitesizebio.com/166/history-of-cell-biology/
- Microscope Slides Preparation - Styles and Techniques. (n.d.). Retrieved from https://www.microscopemaster.com/microscope-slides.html
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