Question

The solute concentration in human red blood cells is equal to that of a 0.9% NaCl solution. Predict what will happen over time when human red blood cells are placed in a beaker of 100% water.

Water will flow into the cells, expanding them slightly, until the solutions inside and outside the cells are isotonic.
Water will continue to move into the cells by osmosis until the cells eventually burst.
Water will move into the cells until the cell membranes exert enough pressure to keep more water from moving in.
Water will flow out of the cells by osmosis until all the cells are completely plasmolyzed.

Answer 1

When red blood cells are placed in pure water, the water enters the cells due to osmosis, causing them to swell and eventually burst in a process known as hemolysis.

Step-by-step explanation:

When human red blood cells are placed in a beaker of 100% water, which is a hypotonic solution, water will move into the cells by osmosis. The osmotic pressure inside the red blood cells is higher than that of the pure water, so water flows into the cells to balance the solute concentrations. This influx of water causes the cells to swell, and over time, they undergo hemolysis, meaning they swell up with water and burst since red blood cells lack mechanisms to prevent excessive water intake, making them susceptible to osmotic pressure changes.