AP BIOLOGY

Detailed explanation-1: -Integral proteins may serve as channels or pumps to move materials into or out of the cell. Peripheral proteins are found on the exterior or interior surfaces of membranes, attached either to integral proteins or to phospholipid molecules.

Detailed explanation-2: -Transmembrane channels, also called membrane channels, are pores within a lipid bilayer. The channels can be formed by protein complexes that run across the membrane or by peptides. They may cross the cell membrane, connecting the cytosol, or cytoplasm, to the extracellular matrix.

Detailed explanation-3: -Aquaporins, belonging to the family of major intrinsic proteins, also form pores in the membrane facilitating mainly the transport of water into and out of the cell. Aquaporins form tetramers in the cell membrane, with each of the four monomers acting as a water channel.

Detailed explanation-4: -The protein that is used to pump the ions through is called a TRANSMEMBRANE (INTEGRAL) protein and it changes its SHAPE to move the ions across the cell membrane.