AP BIOLOGY

Detailed explanation-1: -However, facilitated diffusion differs from passive diffusion in that the transported molecules do not dissolve in the phospholipid bilayer. Instead, their passage is mediated by proteins that enable the transported molecules to cross the membrane without directly interacting with its hydrophobic interior.

Detailed explanation-2: -► Facilitated diffusion is the process by which molecules that cannot directly diffuse across the membrane pass through special protein channels. Osmosis is the facilitated diffusion of water through a selectively permeable membrane. Aquaporins are water channel proteins that allow water to pass through cell membranes.

Detailed explanation-3: -Small nonpolar molecules, such as O2 and CO2, are soluble in the lipid bilayer and therefore can readily cross cell membranes. Small uncharged polar molecules, such as H2O, also can diffuse through membranes, but larger uncharged polar molecules, such as glucose, cannot.

Detailed explanation-4: -Answer and Explanation: Large molecules, polar molecules, and ions, cannot easily pass through the cell membrane. Large molecules, such as glucose, amino acids, and proteins, are simply too big to fit through the phospholipid bilayer.

Detailed explanation-5: -Channel proteins, gated channel proteins, and carrier proteins are three types of transport proteins that are involved in facilitated diffusion. A channel protein, a type of transport protein, acts like a pore in the membrane that lets water molecules or small ions through quickly.