In plant science, we are currently at the dawn of an era, in which mathematical modeling and computational simulations will influence and boost tremendously the gain of new knowledge. However, for many plant scientists mathematical modeling is still rather dubious and is often negligently considered as an oversimplification of the real situation. The goal of this article is to provide a toolbox that allows first steps in the modeling of transport phenomena in plants. The provided framework is applied in the simulation of K+ uptake by cells via K+ channels. Historically, K+ uptake systems are divided into "high affinity" (e. g. H+-coupled K+ transporters) and " low affinity" (K+ channels) transporters. The computational cell biology studies presented here refute this separation. They show that K+ channels are in general uptake systems with " low" and " high affinity" components. The analyses clarify that constraints in wet-lab experiments usually mask the " high affinity" component. Consequently, the channels were widely assigned a " low affinity" component, only. The results presented here unmask the absurdity of the concept of " high-and low-affinity" transporters.