biology questions?

Question

a student put some cells from a tomato plant on a microscope slide, aded a drop of water and observed them under the microscope.after 15 minutes,the cells appeared to be fully expanded.when the student put some blood cell in water on a microscope slide and examined it under high power, no cell could be detected in the sample.what explanation can u suggest for this?

Answer 1

In both situations water will pass through the cell membrane by the process of osmosis. This is because the osmolar concentration of solutes within the cells is higher that outside the cells. You should also point out that the cell membranes of the tomato plant and the red blood cell are semipermeable.

Initially both types of cell will swell as the water passes into the interior of the cell. In the case of the red blood cell, the cell membrane is essentially a phospholipid bi layer and there is no rigid cell wall. After a while the cell will simple burst open because the internal pressure cannot be contained by the cell membrane. Once the cells have lysed they will not be visible under the microscope.

In the case of the tomato plant, the cells will have a rigid cell wall. There will be a bit of flexibility during the initial passage of water but then the cell wall will have the strength to resist cell rupture. Hence you will continue top see the tomato cells.

Answer 2

The blood cells rupture in water because of osmosis. Plants have cell wall that would prevent them from rupturing.

Answer 3

Hint: plant cells have cell walls, animal cells don't.

Answer 4

well, my conclusion would be that mixing tomato cells with water leads to a spontaneous mutation of invisible vampires.