Final answer:
Second messenger systems amplify initial cellular signals and create phosphorylation cascades resulting in substantial physiological effects. These systems allow for sensitive and regulated cellular responses that are crucial for various cellular functions.
Step-by-step explanation:
Advantages of a Second Messenger System
Second messenger systems are a vital aspect of cell communication and signal transduction. Two principal advantages of second messenger systems include their role in amplifying signals and creating a cascade effect. Firstly, a single second messenger molecule can activate many target proteins, leading to the amplification of the initial signal. For instance, cyclic AMP (cAMP) synthesized from ATP by adenylyl cyclase can activate numerous molecules of A-kinase, which in turn phosphorylate many substrates, magnifying the signal many times over.
Secondly, second messenger systems can initiate a phosphorylation cascade, where one kinase activates several others, with each step in the sequence resulting in an exponentially larger cellular response. This cascade effect allows for a highly sensitive and regulated response where even a minute initial signal can have a substantial cellular effect. Hormones that utilize second messenger systems, like angiotensin II and growth hormone-releasing hormone (GHRH), exemplify the tailored responses achieved through such cascades.