The document discusses cell membrane transport and osmosis. It explains that cell membranes are semi-permeable and allow water and some gases to pass through via diffusion down their concentration gradients. Osmosis is defined as the diffusion of water across a semi-permeable membrane from an area of higher water concentration to lower concentration. The document provides examples of how osmosis causes cells to swell or shrink depending if the solutions outside the cell are hypertonic, hypotonic, or isotonic.
2. Cell Membrane Transport In & Out of the Cell Cell membrane is semi-permeable, meaning it is a barrier to most, but not all molecules
3. Cell membranes are bilayers of phospholipids with the hydrophobic regions facing each other and the hydrophilic regions facing out
4. The Fluid Mosaic Model is the theory by which the properties of the plasma membrane are explained. Mosaic: mixture of phospholipids, cholesterol, & proteins Fluid: components may move or shift but are kept ordered due to hydrophobic forces
6. Cell Diffusion H 2 O, CO 2 , & O 2 are among the few molecules that can pass across a cell membrane by diffusion Diffusion The net movement of a substance from an area of high concentration to an area of low concentration. Substances move down their concentration gradient
7. Osmosis : Diffusion of H 2 O across a semi-permeable membrane As the concentration of solute increases the concentration of solvent (H 2 O) decreases Compared to an equal volume of water, the solute/H 2 O mixture has less H 2 O molecules as that space is taken up by the solute
