Second messengers
I. include cGMP
II. are small, soluble molecules
III. are released or generated in response to extracellular signals
IV. include catecholamines

Question

Quizplus · Accepted Answer

Second messengers include cGMP (I), are indeed small, soluble molecules (II), and are released or generated in response to extracellular signals (III). Catecholamines, however, are not second messengers but rather examples of primary messengers or hormones that bind to receptors and may trigger the production of second messengers.

Second Messengers I. Include CGMP