Class 9 Biology - Study of Cells under Microscope

Aim

To observe different types of cells under a microscope and understand their structure and function.

Materials Required

• Microscope
• Glass slide
• Cover slip
• Water
• Onion peel (to observe plant cells)
• Cheek cells (to observe animal cells)
• Stain (such as methylene blue or iodine solution, to highlight cell structures)

Image Reference

Procedure

1. Carefully peel a thin layer from the inner side of an onion bulb for plant cell observation, or gently scrape the inside of your cheek using a clean toothpick for animal cell observation.
2. Place the sample (onion peel or cheek scraping) on a clean glass slide.
3. Add a drop of water to the sample to prevent it from drying.
4. Add a drop of stain (iodine for plant cells or methylene blue for animal cells) to make the cell structures more visible.
5. Gently place a cover slip over the sample to avoid trapping air bubbles.
6. Place the prepared slide under the microscope. Start with the lowest magnification lens to locate the sample and then switch to higher magnifications for detailed observation.
7. Adjust the focus until the cells are clearly visible. Look for cell walls, nuclei, and cytoplasm in plant cells, and cell membranes, nuclei, and cytoplasm in animal cells.

Observation

Under the microscope:

• Onion peel cells: Rectangular-shaped cells with a distinct cell wall, a large vacuole, and a nucleus near the cell wall.
• Cheek cells: Irregularly shaped cells with a thin cell membrane, visible nucleus, and cytoplasm. No cell wall is present.

Inference

This experiment demonstrates the structural differences between plant and animal cells:

• Plant cells have a rigid cell wall, while animal cells do not.
• Both plant and animal cells have a nucleus and cytoplasm.
• Stains help in clearly identifying different cell structures under the microscope.

Video Reference