Chapter 16, Problem 1Q

Summary Introduction

To review:

The epinephrine-stimulated activation of glycogen breakdown and identifying primary signal, receptor, transducer, and response.

Introduction:

There is a requirement of precise regulation of anabolic and catabolic reactions, which utilizes proteins, lipids, and carbohydrates. In multicellular organisms, the regulation of such reactions is complex and is maintained by a constant flow of information. The simplest form of transfer of information includes a primary signal, target, and transducer.

Explanation of Solution

The primary signal in any information flow is the molecule thatis responsible for the initiation of information flow, for example, hormones. In the case of glycogen metabolism, glucagon, insulin, and epinephrine initiate a cascade of events, which involves the conversion of glycogen to glucose-1-phosphate. In the epinephrine-stimulated activation of glycogen breakdown, epinephrine is the primary signal. The receptor, in this case, is the epinephrine receptor to which epinephrine binds.

The transducer is any molecule thatconverts the signal to a cellular response. In this case, the transducer is adenylate cyclase as binding of epinephrine to its receptor activates adenylate cyclase thatconverts ATP (adenosine triphosphate) to cAMP (cyclic adenosine monophosphate), which carries out signal cascade reactions. The response is the final product of the signaling pathway. In epinephrine-stimulated activation of glycogen, breakdown response is the formation of glucose-1-phosphate.

Conclusion

Thus, it can be concluded that the primary signal is epinephrine, the receptor is the epinephrine receptor, the transducer is adenylate cyclase, and the response is glucose-1-phosphate.