What does it mean when we say that a 0.15 M NaCl solution is isotonic with blood, whereas distilled water is hypotonic?

Verified step by step guidance

1. Understand the concept of tonicity: Tonicity refers to the ability of a solution to affect the volume and pressure of a cell by osmosis. It is determined by the concentration of solutes that cannot cross the cell membrane.
2. Define isotonic solution: An isotonic solution has the same solute concentration as another solution, typically referring to the concentration inside a cell. In this case, a 0.15 M NaCl solution is isotonic with blood, meaning it has the same osmotic pressure as blood, preventing net movement of water into or out of cells.
3. Define hypotonic solution: A hypotonic solution has a lower solute concentration compared to another solution. When cells are placed in a hypotonic solution, water enters the cells, potentially causing them to swell and burst.
4. Relate to blood cells: Blood cells in an isotonic solution like 0.15 M NaCl maintain their normal shape and function because there is no net movement of water. In contrast, blood cells in distilled water, which is hypotonic, will swell as water enters the cells.
5. Summarize the importance: Understanding isotonic and hypotonic solutions is crucial in medical and biological contexts to ensure that cells maintain their integrity and function properly.

Key Concepts

Isotonic Solutions

An isotonic solution has the same solute concentration as another solution, typically referring to the comparison between a solution and the cytoplasm of cells. In this case, a 0.15 M NaCl solution is isotonic with blood, meaning it does not cause net movement of water into or out of cells, maintaining cell shape and function.

Hypotonic Solutions

A hypotonic solution has a lower solute concentration compared to another solution. Distilled water is hypotonic relative to blood, which means that if cells are placed in distilled water, water will move into the cells, potentially causing them to swell and burst due to osmotic pressure.

Osmosis

Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process is crucial for maintaining cellular homeostasis, as it influences how cells interact with their surrounding environment, particularly in isotonic and hypotonic conditions.