Signal transduction cascades are produced by molecular assemblies of which of the following components? Enzymes Regulatory proteins Receptors Transmembrane channels Nuclear pores Solution Answer : The correct answer is C (Receptors) Explanation : Receptors are found on the plasmamembrane of the target cells which are bound by primary signal molecules called ligands/hormones. This inturn brings about the synthesis of secondary messengers such as cAMP/cGMP etc., that brings about the changes in cellular physiology through cascade of events..