The document summarizes key aspects of the cell membrane. The cell membrane is selectively permeable, controlling what enters and exits the cell to maintain homeostasis. It is composed of a lipid bilayer with phospholipids that have hydrophilic heads and hydrophobic tails. Proteins are embedded throughout the membrane and act as transporters, sometimes requiring energy to move molecules across. The fluid mosaic model best depicts the structure of the cell membrane.

2. Gatekeeper Regulates what comes in and out of the cell Main components: proteins and phospholipids The cell membrane is selectively permeable Allows some things through without energy, but not everything

3. All cells have a cell membrane Functions : Controls what enters and exits the cell to maintain an internal balance called homeostasis Provides protection and support for the cell TEM picture of a real cell membrane.

4. Found only in plant cells and bacteria cells Main function is support

5. phosopholipids made of two sides: head and tail the head is hydrophillic (able to interact with water) the tail is hydrophobic (not able to interact with water)

6. Structure of cell membrane Lipid Bilayer -2 layers of phospholipids Phosphate head is polar (water loving) Fatty acid tails non-polar (water fearing) Proteins embedded in membrane Phospholipid Lipid Bilayer

7. carrier proteins allow larger or difficult molecules to get through the membrane sometimes they require energy to open/close like a door other times they simply act as a tunnel

8. Proteins Membrane movement animation Polar heads love water & dissolve. Non-polar tails hide from water . Carbohydrate cell markers Fluid Mosaic Model of the cell membrane

9. 4. Cell membranes have pores (holes) in it Selectively permeable : Allows some molecules in and keeps other molecules out The structure helps it be selective! Pores

10. Outside of cell Inside of cell (cytoplasm ) Lipid Bilayer Proteins Transport Protein Phospholipids Carbohydrate chains Structure of the Cell Membrane Go to Section: Animations of membrane structure