An artificial membrane separates two sides of a beaker. the left side contains 50 glucose molecules and the right side contains 100 fructose molecules. if you add channels to the membrane for glucose molecules but do not add any for fructose molecules and then wait for a while, which will more likely be true

Since the channels are only big enough to allow glucose to pass through, it is expected that the fructose molecules will remain unchanged. After an equilibrium time, there would still be 100 fructose molecules on the right and there should be 25 glucose molecules on either side, assuming they distribute evenly.