Chapter 7, Problem 4CTQ

a.

Summary Introduction

To describe:

The reason why red blood cells were not seen in the sample where they were suspended in sterile water.

Concept introduction:

Osmosis occurs when water is transported by fluids across a semi-permeable membrane down the concentration gradient. This process takes place in accordance with temperature, and pressure. If the concentration of solute and free water molecules is same, the solution is isotonic and doesn’t involve any movement of water across the semi-permeable membrane. When a solution with varying concentrations is divided by a semi-permeable membrane, a solution that contains higher concentration is calledit as a hypertonic solution and that is more diluted is called isotonic solution.

b.

Summary Introduction

To describe:

The consequence of suspending bacterial cells in sterile water.

Concept introduction:

If the concentration of solute and free water molecules is same, the solution is isotonic, and it does not involve any movement of water across the cell membrane by osmosis. When a solution with varying concentrations is divided by a membrane, the area with higher concentration is the hypertonic solution and the area which is more diluted is called as the isotonic solution. Osmosis always occurs down the concentration gradient (from low concentration to high concentration).