PLASMA MEMBRANE The plasma membrane serves as the
PLASMA MEMBRANE • The plasma membrane serves as the boundary between the cell and its environment • Allows specific amount of nutrients to enter and allow waste to exit
HOMEOSTASIS • All organisms must maintain a balance regardless of internal and external conditions • This task is controlled by the plasma membrane
PLASMA MEMBRANE • Contains cell contents • Double layer of phospholipids & proteins
THE PHOSPHOLIPID…. . LETS TAKE A CLOSER LOOK! • Phosphate Head • Hydrophilic • Polar • Fatty Acid Tail • Hydrophobic • Nonpolar
MOVEMENT ACROSS THE PLASMA MEMBRANE • A few molecules move freely across the membrane • Water, Carbon dioxide, Ammonia, Oxygen • Carrier proteins transport other larger molecules and ions • Proteins embedded in lipid bilayer
MEMBRANE PROTEINS Channels proteins or transporters • Move molecules in one direction Receptors • Recognize certain chemicals Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins
CHARACTERISTICS OF CELL MEMBRANE • Selectively permeable – allows some molecules to enter and keeps others out • Like a screen door
PLASMA MEMBRANE • Made up of two layers of phospholipids • Controls what moves into and out of the cell • Selectively permeable • AKA: Lipid Bilayer, Fluid Mosaic, Cell Membrane
- Slides: 9