Suppose you found a molecule a, which had a molecular mass of 1500 daltons, was able to penetrate the channels of a gap junction, but molecule b whose molecular mass was only 1200 daltons, was unable to diffuse between the same cells. how might these molecules be different so as to explain these results?

The rate that would change would be the  searching efficiency/attack rate. there are only two other rates in this model: the  growth rate of prey, and the  predator or consumer mortality rate.the  searching efficiency/attack rate is what indicates how effectively can a predator capture its prey whether in the searching process or actual capturing/attacking process.