Questions: How is water different from saline in terms of its tonicity? In this scenario, what effect on the residual malignant cells is the surgeon trying to achieve by use of the sterile water? Compare and contrast the osmotic reactions that occur between eukaryotic and prokaryotic cells when placed in hypertonic or hypotonic solutions. Discuss the other differences between eukaryotic cells and prokaryotic cells.

Water and saline differ in terms of tonicity as follows:

1. Tonicity of Water vs. Saline:

   • Water: Pure water is hypotonic relative to most biological cells. This means that it has a lower concentration of solutes compared to the inside of the cell.
   • Saline: Saline solutions, such as normal saline (0.9% NaCl), are isotonic to human cells. This means that the concentration of solutes in the saline is similar to that inside the cells, preventing net movement of water across the cell membrane.

2. Effect on Residual Malignant Cells Using Sterile Water:

   • When sterile water is used on residual malignant cells, the surgeon aims to exploit the hypotonic nature of water. The water will cause an influx into the cells due to osmosis, leading to cell swelling and potentially causing the cells to burst (lyse). This can help in destroying any remaining cancerous cells.

3. Osmotic Reactions in Eukaryotic vs. Prokaryotic Cells:

   • Eukaryotic Cells: When placed in a hypertonic solution, eukaryotic cells will lose water and shrink (crenate). In a hypotonic solution, they will gain water and may swell and burst (lyse) due to the lack of a rigid cell wall.
   • Prokaryotic Cells: Prokaryotic cells, such as bacteria, have a rigid cell wall that provides structural support. In a hypertonic solution, they will also lose water, leading to plasmolysis where the cell membrane pulls away from the cell wall. In a hypotonic solution, they will gain water, but the cell wall prevents them from bursting, although they may become turgid.

In summary, water is hypotonic compared to saline, which is isotonic. The use of sterile water aims to lyse malignant cells by causing them to swell and burst. Eukaryotic cells are more susceptible to bursting in hypotonic solutions due to the lack of a cell wall, while prokaryotic cells are protected by their rigid cell wall.