Define the terms hypotonic, hypertonic, and isotonic and discuss their relationship to osmotic pressure

Question

What will be an ideal response?

Answer 1

When water solutions of unequal salinity are separated by a semipermeable membrane (such as skin or the membrane around a living cell), water molecules (but not dissolved ions) diffuse through the membrane. To equalize the salt concentration on both sides of the membrane, water molecules always move from the less concentrated solution into the more concentrated solution in a process called osmosis. Osmosis is diffusion that produces a net transfer of water molecules through a semipermeable membrane from the side with the greatest concentration of water molecules to the side with the lesser concentration of water molecules. An organism is hypotonic relative to the water outside its body if the salinity within an organism's cells is less than that of the surrounding seawater, water from the cells will pass through the cell membranes out into the seawater (toward the more concentrated solution). An organism is hypertonic if seawater has a lower salinity than the fluid within an organism's cells; seawater will pass through the cell walls into the cells (always toward the more concentrated solution). If the salinity of an organism's body fluid equals that of the ocean, it is isotonic and has equal osmotic pressure, and so no net transfer of water will occur through the membrane in either direction.