porecomplexes NPCs is plotted for four molecules A to D as a

porecomplexes (NPCs) is plotted for four molecules (A to D) as a function of time, starting from anarbitrarily chosen initial concentration difference. Indicate which curve corresponds to each ofthe following molecules. Put the letter in the corresponding parenthesis.
(   )     A large protein that is being actively transportedacross the NPC
(   )     A small water-soluble molecule

(   )     A small protein composed of a few dozen residues

(   )     A large protein that is NOT actively transported
into or out of the nuclear.

Concentration difference across the nuclear envelope (nM)

Solution

Here the order will be A, B, D, C. (Since a large protein which is actively transported across the membrane, will require energy to move across the membrane and hence the movement across membrane will be almost zero and hence there will be a huge concentration difference with time, which is indicated by the curve A. Curve C indicating the decrease in concentration difference with time, which supports the last parenthesis, because the molecule is large but not actively transported, hence it will not require energy to move across membrane hence there will be change in concentration difference but not more than a small protein composed of a few dozen residues.