The dependence of lag time on glucose pulse frequency can be explained with constitutive degradation of the limiting entity. In the model shown, the entity abundance is synthesized with each glucose pulse and depletes constitutively. Three example frequencies (f1 > f2 > f3) are shown where slight changes in period time dramatically changes the time for the entity to reach the threshold needed to engender division. When synthesis and degradation of the entity are equal, the TI feedrate is at the critical rate (f3). Arrows indicate the glucose pulse frequency 