Fill in the blands:
(a) Some carrier of transport protenis allow diffusion only if two types of molecules move together. In ..... 1 ...... Both molecules, cross the membrane in the same directions, in ..... 2 ...... They move in opposite directions.
(b) When a molecule moves across a membrane independent of other molecules, the process is called .... 3 .....

Options

A. 1-Uniport, 2-Symport, 3-Antiport
B. 3-Uniport, 1-Symport, 2-Antiport
C. 2-Uniport, 3-Symport, 1-Antiport
D. 3-Uniport, 2-Symport, 1-Antiport

Answer

B

Explanation

Some carrier or transport proteins allow diffusion only if two types of molecules move together. In symport both molecules cross the membrane in same direction, in antiport they move in opposite directions.
(b) When a molecule moves across a membrane independent of other molecules, the process is called uniport.