In the simulation, when protein molecules were evenly distributed on both sides of the membrane, was the solution isotonic, hypertonic, or hypotonic? Which direction was water flowing?

1. Diffusion is the process of a substance moving from an area of high concentration to an area of lower concentration. Osmosis is a type of diffusion where water moves across a semipermeable membrane still from an area of high concentration of water to an area of lower concentration of water. This corresponds to water moving from an area with a low concentration of solute to an area with a higher concentration of solute.

2.

a. A semipermeable membrane allows some substances to pass through it.

b. The plasma membrane of a cell allows small uncharged molecules to pass through it, but not large molecules and not charged ions.

3.

a. The protein molecules were evenly distributed on both sides of the membrane, so this solution was isotonic.

b. In an isotonic solution, water moves both in and out of the cell, which was observed in the simulation.

4.

a. The protein molecules were more highly concentrated on the inside of the cell, so this solution was hypotonic.

b. In hypotonic solutions, water moves into the cell to help dissolve the higher amount of solute inside the cell, which was observed in the simulation.

5.

a. A semipermeable cell membrane is important to allow some molecules, like proteins, to be more highly concentrated inside the cell than outside the cell. If the cell membrane were permeable, the molecules on the inside of the cell would exit the cell and be evenly distributed in the cell and in its environment.

b. If the cell membrane were not permeable at all, the cell would not be able to receive nutrients from its environment.

Explanation: