Abstract
The concept of time-arrow does not appear frequently in physics. This is not the case for the study of biochemical systems as many of them are able to sense whether a variable is increasing or decreasing. This effect can be explained by the non-linear character of the system and its dynamics.
Keywords: Bound enzymes and hysteresis loops, Time-arrow and non-linearity of sequences of biochemical reactions, Non-linearity and sensing chemical signals, Sensing the direction of a process.