Model of Plasma Membrane Lipid Bilayer Two layers of phospholipids Polar Phosphate group Nonpolar Fatty acids
Lipid Bilayer Polar phosphate group dissolves in water Point toward the outside and inside of the cell (toward water) Nonpolar fatty acids DO NOT dissolve in water Point toward the middle of membrane
Dynamic structure Fatty acid tails wave back and forth Phospholipids glide through bilayer Cholesterol Embedded in membrane Rigid Restrict phospholipid movement
Membrane Proteins Embedded throughout bilayer Lie on inner or outer surface Polar and nonpolar portions Migrate
Fluid Mosaic Model Fluid-Components of membrane are constantly moving Mosaic- random pattern of proteins Cell organelles have membranes with the “fluid mosaic” structure.