2.7

• Membrane proteins are needed for facilitated diffusion
• Facilitated Diffusion is required for large and small polar molecules
• • Large quantities of water pass through aquaporins
• • Charged ions, including Na+ and K+ require channel proteins
• • Ion - Charged particle
• Active transport maintains and establishes concentration gradients.
• Active transport moves molecules and ions against the concentration gradient from low to high
• Active Transport requires metabolic energy (such as ATP)
• Cotransport is a type of secondary active transport that uses the energy from an electrochemical gradient to transport two different ions across the membrane through a protein.
• Symport is a type of transport where two different ions are transported in the same direction.
• Membrane proteins are necessary for active transport.
• Antiport is the movement of two different ions are transported in opposite directions
• Membranes may become polarized by movement of ions.