AP BIOLOGY

Detailed explanation-1: -A channel protein, a type of transport protein, acts like a pore in the membrane that lets water molecules or small ions through quickly. Water channel proteins (aquaporins) allow wate r to diffuse across the membrane at a very fast rate. Ion channel proteins allow ions to diffuse across the membrane.

Detailed explanation-2: -Channel proteins span the membrane and make hydrophilic tunnels across it, allowing their target molecules to pass through by diffusion. Channels are very selective and will accept only one type of molecule (or a few closely related molecules) for transport.

Detailed explanation-3: -Channel proteins are proteins that create hydrophilic holes in cell membranes, facilitating the transport of molecules down the concentration gradient. Carrier proteins are integral proteins that transport chemicals across the membrane both down and up the concentration gradient.

Detailed explanation-4: -Channel Protein Structure Non-gated channels are usually formed from identical subunits, which attach to each other in a circle. While the inside of the circle is hydrophilic, the amino acids exposed within the hydrophobic cell membrane are also non-polar. This helps to anchor the protein within the membrane.

Detailed explanation-5: -Channel proteins are transmembrane proteins that move molecules from high to low concentration without binding to them or using energy. Because they do not use energy, channel proteins are a form of passive transport.