Aquaporins are proteins that control the passage of water molecules across the cell membrane.The protein forms a pore,or opening,in the membrane.You isolate what you think are two different molecules of aquaporin,and determine that one of the proteins has a larger pore diameter than the second.Which of the following do you conclude?
A)These two forms of aquaporin will have identical sequences of amino acids.
B)These two forms of aquaporin will have different sequences of amino acids.
C)You will have to sequence the proteins to compare their primary structure,because it should have no effect on pore diameter.
D)These molecules both can't have aquaporin because all proteins that do the same type of job (such as catalyze a reaction)have the exact same 3-D structure.

Question

Quizplus · Accepted Answer

The diameter of the pore in the cell membrane is determined by the 3-D structure of the protein, which is in turn determined by its amino acid sequence. Therefore, if the two forms of aquaporin have different pore diameters, they must have different sequences of amino acids that result in different protein structures.

Aquaporins Are Proteins That Control the Passage of Water Molecules