Question

A transmembrane protein has the following properties: it has two binding sites, one for solute A and one for solute B. The protein can undergo a conformational change to switch between two states: either both binding sites are exposed exclusively on one side of the membrane or both binding sites are exposed exclusively on the other side of the membrane. The protein can switch between the two conformational states only if both binding sites are occupied or if both binding sites are empty, but cannot switch if only one binding site is occupied. What kind of protein do these properties define

Answer 1

The protein is a symport protein.

Step-by-step explanation:

Transport proteins are proteins which are involved in the transport of solutes across the cell membrane. The binding of the solute to be transported across the membrane causes a conformational change in the shape of the protein, thereby moving the molecule to the side of nthe membrane it is to be transported. The difference in the concentration of the solute across the membrane known as concentration gradient is mainly responsible for the transport of molecules by the transport proteins.

There are three types of transport proteins: uniport, symport and antiport transport proteins.

Uniporters are involved in moving only one molecule across a membrane

Symporters are involved in moving two or more molecule across a membrane in the same direction.

Antiporters are involved in moving two or more molecule across a membrane in opposite directions.

From the description of the transport protein in the question, both solutes A and B are moved across the membrane simultaneously in the same direction. Therefore, the protein is a symport protein.