G protein‑coupled receptors (GPCRs) transform external stimuli to intracellular signals. The G protein associated with the receptor is activated by ligand binding, regulating an enzyme that produces a second messenger. The second messenger, in turn, brings about changes within the cell. Components of two common second messenger pathways are given. Identify the next component of each signaling pathway. Each compound or ion may be used once or more than once. One target requires two answers. The given abbreviations are used: cAMP, cyclic AMP; DAG, diacylglycerol; IP3, inositol triphosphate; PIP2, phosphatidylinositol 4,5‑bisphosphate; PKA, protein kinase A (cAMP‑dependent protein kinase); PKC, protein kinase C; PLC, phospholipase C.

The earth's moon is unusually large. two popular theories of the moon's origin include the "sister world" hypothesis, which states that the moon formed from the same materials as the earth, near enough to the earth that they fell into orbit around each other. a second theory is the "capture" hypothesis, in which the moon formed elsewhere in the solar system, and the earth's gravity pulled it into its orbit. studies of what the moon is made of indicate that some of its materials had to come from the earth or from the same area of the solar system where the earth had formed. at the same time, the moon does not contain much of the material that makes up the earth's core, so the moon could not have formed from the same materials as the earth. how do the two facts above affect the described theories of the moon's origin? a. they show that scientists will never agree on where the moon came from. b. they show that more experiments on moon formation need to be done. c. they show that no theory accounts for the existence of the moon. d. they show that neither theory is complete and entirely correct.

Why is soap used to remove grease? a. its nonpolar end dissolves the grease. b. it makes the water bond with the grease. c. it chemically bonds with the grease. d. its polar end dissolves the grease. correct answer for apex - a, its nonpolar end dissolves the grease.

What are the chemical names of these compounds? ke: mg3n2: reset next