AP BIOLOGY

Detailed explanation-1: -A gated channel protein is a transport protein that opens a “gate, ” allowing a molecule to pass through the membrane. Gated channels have a binding site that is specific for a given molecule or ion.

Detailed explanation-2: -Proteins act as a gateway allowing or not allowing the transport of some molecules into and out of the cell, making the membrane a selective barrier. The cell membrane is known as the fluid mosaic model owing to its fluidity and lateral movement of proteins across the membrane.

Detailed explanation-3: -Carrier proteins bind specific molecules to be transported on one side of the membrane. They then undergo conformational changes that allow the molecule to pass through the membrane and be released on the other side.

Detailed explanation-4: -However, because they are charged or polar, they can’t cross the phospholipid part of the membrane without help. Facilitated transport proteins shield these molecules from the hydrophobic core of the membrane, providing a route by which they can cross.