1. If the red blood cells (RBCs) of human blood are isolated and diluted in normal saline (an isotonic solution to blood), what will happen to the RBCs?
If red blood cells are isolated and kept in a saline solution (isotonic to blood), the red blood cells will neither swell nor shrink.
The concentration of salt inside the red blood cells is regulated by the cell's semipermeable membrane, which allows water and small molecules to pass through but restricts the movement of larger molecules such as proteins and other cell components.
If the concentration of salt outside the cell is too high (hypertonic), water will flow out of the cell, causing the cell to shrink and possibly become dehydrated. If the concentration of salt outside the cell is too low (hypotonic), water will flow into the cell, causing it to swell and possibly burst (lyse).