1. Preparation
* Safety First:
* Wear gloves to protect yourself from potential contaminants.
* Use a clean workspace and disinfect it before and after use.
* Materials:
* Microscope: A compound light microscope is essential.
* Slides and Coverslips: Clean and grease-free.
* Pipette: For transferring cells.
* Dissecting Kit: For careful dissection.
* Petri Dish: For keeping the cells moist.
* Physiological Saline or Buffer Solution: To maintain the cells' viability and shape.
* Staining Solutions (Optional): Methylene blue, iodine, or other dyes to enhance visibility of specific cell structures.
2. Obtaining Animal Cells
* Source:
* Living Organisms: Students can gently scrape cells from the inside of their cheek (epithelial cells) or use a sterile swab to collect cells from the inner lining of their nose (nasal epithelial cells).
* Animal Tissues: Obtain prepared tissue samples from a biology supply company.
* Dissection:
* If using tissue, perform the dissection with care.
* Avoid damaging the cells as much as possible.
3. Creating the Fresh Mount
* Transferring Cells:
* Use a pipette to transfer a small amount of the collected cells or tissue to a clean slide.
* For cheek cells, gently scrape the inside of your cheek with a sterile swab and then smear the swab on the slide.
* Adding Saline/Buffer:
* Add a drop of physiological saline or buffer solution to the slide. This will keep the cells hydrated and prevent them from drying out.
* Covering with a Coverslip:
* Carefully lower a coverslip onto the slide, avoiding air bubbles. You can use a thin piece of paper or a forceps to help place the coverslip.
4. Observing under the Microscope
* Focusing: Start with the lowest power objective lens and slowly adjust the focus until the cells are clear.
* Illumination: Use the light source of your microscope effectively to illuminate the cells.
* Identifying Features:
* Animal Cells: Observe the cell membrane, cytoplasm, nucleus, and possibly other organelles like mitochondria (depending on the cell type).
* Staining: If using stains, observe how they highlight specific cell structures.
5. Recording Observations
* Drawings: Create detailed diagrams of what you see.
* Labels: Label the key structures you've identified.
* Write a Description: Document your observations, including cell shape, size, and any interesting features you notice.
Important Considerations:
* Cell Viability: Fresh mounts are best observed immediately, as cells will start to deteriorate over time.
* Ethics: If using living organisms, make sure the procedures are humane and minimize any discomfort.
* Disposal: Dispose of all materials properly according to your school's safety guidelines.
Safety Tips:
* Wear lab goggles to protect your eyes.
* Wash your hands thoroughly after handling animal cells.
* Report any spills or accidents to your teacher immediately.
