Facilitated diffusion is passive transport of solutes across membranes using transport proteins. Molecules move from high to low concentration without requiring ATP. Lipid bilayer restricts movement of hydrophilic and polar molecules
Cell membrane is a thin, living layer surrounding and limiting cells. Eukaryotic membranes contain 50% lipids and 50% proteins. Prokaryotic membranes contain 40% lipids and 60% proteins. Fluid Mosaic Model shows proteins floating in lipid bilayer. Membrane proteins can be integral (embedded) or peripheral (surface)
Cell membrane separates cell contents from environment and provides protective barrier. Composed primarily of phospholipid bilayer with cholesterol and embedded proteins. Phospholipid heads are hydrophilic and attracted to water, tails are hydrophobic. Membrane remains fluid and contains both integral and peripheral proteins
Cell membrane separates internal and external environments. Transport occurs via active and passive processes. Molecules are transported between cells and excreted out
Facilitated diffusion is passive transport of substances across membranes using transport proteins. Moves substances from high to low concentration without requiring chemical energy. Driven by kinetic energy and requires membrane proteins for assistance
Concentration gradient is the gradual change in solute concentration over distance. Results from unequal distribution of particles between intracellular and extracellular fluids. Solutes move from high to low concentration areas to establish equilibrium