Cell Membrane Notes PDF

**Cell Membrane Notes** **Phospholipid Bilayer** - The cell membrane is composed of \_\_lipids\_\_\_\_\_\_\_\_\_\_\_\_\_\_ and proteins separating the cell contents from the outside world. It is a "bi-layer" because it consists of \_\_2\_\_\_ layers of \_phospholipids\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_...

**Cell Membrane Notes** **Phospholipid Bilayer** - The cell membrane is composed of \_\_lipids\_\_\_\_\_\_\_\_\_\_\_\_\_\_ and proteins separating the cell contents from the outside world. It is a "bi-layer" because it consists of \_\_2\_\_\_ layers of \_phospholipids\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ arranged so that they are facing \_\_\_away\_\_\_\_\_\_\_\_\_\_ from each other. **Phosphate Heads** - they are \_\_hydrophilic\_\_\_\_\_\_\_\_\_\_\_\_ (They like water and orient themselves towards the water). **Lipid Tails** - they are \_\_\_hydrophobic\_\_\_\_\_\_\_\_\_\_\_\_\_ (They fear the water and face away from the water. **The Fluid Mosaic Model** - This is a "model" that more accurately depicts the \_structure\_\_\_\_\_\_\_\_\_\_\_\_\_ of the cell membrane. It is called "fluid" because and a "mosaic" because  Cell Membranes are \_\_\_semipermeable\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. This means that they only allow certain things to pass through. *[How Things Move]* **Diffusion** - This is the movement of \_\_\_liquid\_\_\_\_\_\_\_\_\_\_\_\_ or \_\_gas\_\_\_\_\_\_\_ molecules from an area of \_\_high\_\_\_\_\_\_\_\_\_\_ concentration to an area of \_\_\_low\_\_\_\_\_\_ concentration. **Osmosis** - This is the diffusion of \_\_\_water\_\_\_\_\_\_\_\_\_\_\_ across a semipermeable membrane. One factor that can influence the movement of water molecules is the solute concentration. **Hypertonic Solution** - This is a comparative term. Hyper means \_\_high\_\_\_\_\_ and tonic refers to the \_\_solute\_\_\_\_\_\_\_\_\_\_\_. If a cell is placed in a solution that is hypertonic (it has more dissolved \_\_solutes\_\_\_\_\_\_), the hypertonic solution will \_\_\_\_force water out of the cell\_\_\_\_\_\_\_\_\_. This occurs because the concentration of solutes \_\_\_outside\_\_\_\_\_\_\_\_\_\_\_ of the cell is greater than the concentration of solutes \_\_\_inside\_\_\_\_\_\_\_\_ of the cell. For example: if you place a cell in saltwater, the cell will shrivel and die. **Hypotonic Solution** - Hypo means \_low\_\_\_\_\_\_. If a cell is placed in a solution that is hypotonic, the cell will swell and possibly \_\_\_burst\_\_\_\_\_\_\_\_.  **Isotonic Solution** - This is when there is a \_\_\_balance\_\_\_\_\_\_\_\_\_\_\_\_ outside and inside of the cell. *[Other Types of Movement Across a Membrane]*: **Facilitated Diffusion** - To facilitate means to \_\_\_help along\_\_\_\_\_\_\_\_\_\_\_. Facilitated Diffusion occurs when \_\_carrier proteins\_\_\_\_\_\_\_\_\_ are used to move molecules through a cell membrane. The proteins change their \_\_\_shape\_\_\_\_\_\_ to allow molecules to pass through. This is a \_passive\_\_\_\_\_\_\_\_\_ process as it does not require \_\_\_energy\_\_\_\_\_\_\_\_\_\_\_.  **Active Transport** - This process requires \_\_\_\_energy\_\_\_\_\_\_\_\_\_\_\_ to transport molecules through a cell membrane. An example of this would be the \_\_Na K Pump\_\_\_\_\_\_\_\_\_\_\_ in muscle contraction. This is typically against the concentration \_\_\_gradient\_\_\_\_\_\_\_\_. **Bulk Transport** - This involves the movement of \_\_large\_\_\_\_\_\_\_\_ molecules across a membrane. When this happens, the molecules become \_\_\_\_wrapped\_\_\_\_\_\_\_\_\_\_\_\_\_ in the membrane as they move across. **Endocytosis** - is bulk transport \_\_\_into\_\_\_\_\_\_\_\_\_\_\_ a cell.  **Exocytosis** - is bulk transport \_out of \_\_\_\_ a cell. **Receptor Mediated Endocytosis** - this involves the use of cell-surface \_\_\_receptors\_\_\_\_\_\_\_\_\_\_\_.