What characterizes an isotonic solution?

An isotonic solution is characterized by having equal osmolarity to another solution. This means that the concentration of solutes is the same on both sides of a semipermeable membrane, resulting in no net movement of water into or out of the cell. When cells are placed in an isotonic solution, they maintain their normal shape and function, as there is no osmotic pressure difference that could cause them to swell or shrink.

In the context of cellular biology, isotonic solutions are crucial because they help to maintain homeostasis in cells and tissues. This concept is especially important in medical and clinical settings, such as when intravenous fluids are administered to patients. Using an isotonic solution can prevent cellular damage from excessive swelling or shrinkage caused by the movement of water across cell membranes.

The characterization of isotonic solutions is foundational in understanding fluid balance, cellular metabolism, and various physiological processes.