Ion channels and cellular transport structures belong to this classification of

Transporters

Explanation:

All proteins interacting with the cell membrane are called membrane proteins. A subclass of such proteins are the transporters which are involved in the transport of different kind of substances inside or outside the cell. This substances can be ions or macromolecules depending on the portein structure.

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%