48.Choose the correct combination: A. Uniport system-Diffusion of two types of molecules together B. Symport system-Diffusion of one molecule C. Antiport system-Diffusion of two types of molecules together in opposite directions D. Antiport system-Diffusion of two types of molecules together in the same direction
Option C.Some carrier proteins allow transport only if two types of molecules move together. This is called cotransport. It is of two types: symport and antiport method. In symport method of cotransport, both molecules cross the membrane in the same direction at the same time. In antiport method of cotransport, both molecules move in opposite direction. When a molecule move across a membrane independent of other molecule, the process is called uniport.
