Osmosis: Cell Wall and Cover Slip

Introduction:

Humans sometimes don’t know why phenomenon or things happen. They just accept it without knowing the cause of it. And there is no meaning in it if we just accept things without reasons. That’s why this experiment is conducted so that we may know how things happen in the level of cells.

Objectives:

1. To demonstrate the principle of Osmosis and to apply it with actual life situations.

Materials and Methods:

• Materials:
 Compound microscope
 Glass Slide
 Cover Slip
 Tissue Paper
 Blade
 Rhoeo discolor Leaves
 Salt Solution

• Procedures:

 Place a drop of distilled water on a clean glass slide.
 With the use of a blade, cut a thin slice of the lower epidermal leaf (red violet in color) of the Rhoeo discolor.
 Place the thin slice of the leaf on the glass slide with a cover slip and focus under LPO. Take note that the cytoplasm of the cells is red violet in color. This is due to the pigment called anthocyanin dissolved in their cytoplasm. Draw your observation.
 Place some salt solution at the edge of the cover slip. The salt solution will seep through the specimen even without opening the cover slip. Observe the Rhoeo discolor under the microscope. What happened to the cells? Draw your observation.
 Draw out the salt solution from the specimen by placing dry tissue paper at the edge of the cover slip.
 Place drops of pure water at the edge of the cover slip. Observe what happened to the cells. Draw your observation.

Discussion
Questions:
1. What happened to the onion skin after flooding it with salt solution? What could be a possible explanation to such observation? o Crenation happens (where the cytoplasmic contents of the cell pull away from the rigid cell wall) because the onion skin is exposed to a hypertonic solution (where the water solution on the cell is greater than that of the outside) and by osmosis, the water goes out of the cell, this process is called Plasmolysis.
2. What happened to