Question

Explain the difference between hypertonic and hypotonic, using human cells as a reference point. (p. 56)

Short answer

Short Answer: Hypertonic solutions have a higher solute concentration compared to the cell, causing water to move out of the cell and leading to cell shrinkage. Hypotonic solutions have a lower solute concentration compared to the cell, causing water to move into the cell and resulting in cell swelling. The movement of water occurs due to osmosis in an effort to equalize the solute concentrations on both sides of the cell membrane.

Step-by-step solution

Define Hypertonic and Hypotonic Solutions

Hypertonic solutions have a higher concentration of solutes (dissolved substances) than the cell, while hypotonic solutions have a lower concentration of solutes compared to the cell. These solutions are relative to the environment surrounding the cell, which affects the movement of water in and out of the cells through a process called osmosis.

Osmosis

Osmosis is the movement of water molecules across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration. This process continues until the concentration of solutes on both sides of the membrane becomes equal, reaching a state called isotonic equilibrium.

Human Cells in Hypertonic Solutions

When human cells are placed in a hypertonic solution, the concentration of solutes outside the cell is higher than that inside the cell. As a result, water will move out of the cell through osmosis, trying to equalize the solute concentration on both sides of the cell membrane. In this process, cells lose water, causing them to shrink and eventually leading to cell damage or death (called crenation).

Human Cells in Hypotonic Solutions

In the case of hypotonic solutions, the concentration of solutes outside the cell is lower than that inside the cell. This causes water to move into the cell through osmosis in an attempt to equalize solute concentration on both sides of the cell membrane. Consequently, cells absorb more water, which leads to swelling and the potential rupture of the cell (called lysis).

Conclusion

In summary, hypertonic solutions cause human cells to shrink, while hypotonic solutions cause them to swell. The key to understanding the difference between these solutions is the behavior of water molecules during osmosis. Maintaining an isotonic environment, where the concentration of solutes inside and outside the cell is equal, prevents potential cell damage due to hypertonic or hypotonic conditions.