Question

What will happen when red blood cells are placed in:
(a)Pure water
(b)Concentrated solution for some time

Answer 1

Hint: Red blood cells carry oxygen with help of hemoglobin in the entire body. Osmosis is the movement of water molecules across a semipermeable plasma membrane from a region of lower concentration solution to a region of higher concentration solution.

Complete Answer:
A red blood cell that is placed in a hypotonic solution, i.e. a solution with a lower concentration, the cell will swell as a result of more water moving into the cell than out. This may lead to potential hemolysis (bursting) of the cell. Pure water is a hypotonic solution compared to red blood cells, hence if placed in it the cell will swell.
When red blood cells are in a hypertonic solution, i.e. higher concentration solution, water moves out of the cell faster than it comes in. This results in shrinking (shriveling) of the blood cell. The concentrated solution is a hypertonic solution compared to red blood cells, hence if placed in it the cell will shrivel.

Additional information:
-Due to the Osmosis process, water moves into and out of cells.
-If a cell is placed in a hypertonic solution, means the solution contains a lower water concentration than the cell cytosol, then water moves out of the cell until both solutions are isotonic.
-If cells are placed in a hypotonic solution, i.e. the solution has a higher water concentration than the cell cytosol, it will take in water across their membranes until both the external solution and the cytosol are isotonic.

Note: The difference in the concentrations of the molecules in the two regions, i.e. inside and outside the cell, is called the concentration gradient. Osmosis will take place until the concentration gradient has been eradicated.