Figure 1

cAMP pathway is a good example of signal amplification: one hormone molecule can lead to formation of many cAMP molecules. Low levels of cAMP allow large fractional increase and decrease in the concentration of cAMP with small amounts of cAMP made or broken down, so that the activation and deactivation can be rapid. As depicted here, cAMP increases to the peak soon as it is activated and then degraded dramatically at around 10 seconds. The figure was produced with the BioNessie.