The correct answer is option 3. Same osmotic pressure.
Isotonic solutions refer to solutions that have the same osmotic pressure across a semipermeable membrane. To understand this concept in more detail, let's break it down:
1. Osmosis:
Osmosis is the movement of solvent molecules (usually water) across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. The goal is to equalize the concentration of solutes on both sides of the membrane.
2. Osmotic Pressure:
Osmotic pressure is the pressure exerted by the movement of solvent molecules during osmosis. The more concentrated the solute solution, the higher the osmotic pressure.
3. Isotonic Solutions:
In the context of biological systems (e.g., cells), isotonic solutions are those that have the same concentration of solutes as the cytoplasm of the cell.
When a cell is placed in an isotonic solution, the movement of water into and out of the cell is balanced. There is no net movement of water, and the cell maintains its shape and size.
4. Significance of Isotonic Solutions:
For cells, maintaining an isotonic environment is crucial for proper functioning. In a hypotonic solution (lower solute concentration outside the cell), water would enter the cell, causing it to swell and potentially burst (lyse). In a hypertonic solution (higher solute concentration outside the cell), water would leave the cell, causing it to shrink (crenate).
In medical contexts, intravenous (IV) solutions are often adjusted to be isotonic with blood to prevent damage to red blood cells and other cells.
5. Examples of Isotonic Solutions:
Normal saline (0.9% NaCl) is a commonly used isotonic solution in medical settings.
Ringer's solution is another isotonic solution used for intravenous administration.
In summary, isotonic solutions are characterized by having the same osmotic pressure, and they play a crucial role in maintaining the proper balance of water and solutes in biological systems. |
