Signal transduction molecular circuits

Signal Transduction Depends on Molecular Circuits An Overview... 

Signal-transduction pathways follow a broadly similar course that can be viewed as a molecular circuit (Figure 151). We begin by examining the challenges posed by transferring extracellular information to a cell s interior. 

Molecular switches. Signal transduction circuits in biological systems have molecular on/off switches that, like those in a computer chip (above), transmit information when "on." Common among these are G proteins (right), which transmit a signal when hound to GTP and are silent when bound to GDP. [(Left) Courtesy of Intel.]... 

Draw a generalized molecular circuit based on a signal transduction cascade. Outline the roles of membrane receptors, ligands, primary messengers, second messengers, and protein phosphorylation in the process. 

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