In the context of osmosis, what happens to red blood cells placed in distilled water?

• A. They actively pump water out to maintain their normal volume.
• B. They swell and may lyse (hemolyze) because water moves into the cells.
• C. They shrink (crenate) because water moves out of the cells.
• D. They remain unchanged because there is no net water movement.

Answer: (B)

Verified step by step guidance

1. Understand the concept of 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.
2. Identify the environment of the red blood cells: Distilled water is a hypotonic solution, meaning it has a lower concentration of solutes compared to the inside of the red blood cells.
3. Predict the direction of water movement: Since water moves from areas of low solute concentration to high solute concentration, water will move into the red blood cells from the distilled water.
4. Consider the effect on red blood cells: As water enters, the cells will swell because their internal solute concentration is higher, causing an influx of water to balance the concentration.
5. Understand the possible outcome: If too much water enters, the red blood cells may swell excessively and eventually burst, a process called hemolysis.