oxygen molecules green . Some molecules are too large to pass through the membrane. Molecules like glucose, which is a sugar molecule, must use special proteins embedded in the membrane to move into the cell. These proteins are called channel proteins, and they provide an opening, like a door, for large molecules to pass. Glucose will also move from areas of high concentration to low concentration, but because it needs the help of a protein, the process is called facilitated diffusion. Color all the glucose molecules (d) purple . Color the channel protein (a) yellow .
Osmosis is a Special Kind of DiffusionOsmosisis the process where water moves across the membrane toward the area with the highest solute concentration. A soluteis a compound, like salt or sugar, that is dissolved in water. Hypertonicsolutions have more solute in them, which cause water to move toward that area. Cells placed in hypertonic solutions will lose water and shrink. Solutions that have less solute molecules than the cell are called hypotonic. In this case, water from outside the cell will move into the cell. The cell will gain water, expand, and could even burst. To summarize, the side with MORE solute is said to be hypertonic, and the side with less is said to be hypotonic.