Protein kinase A itself is different in different cell types, which explains why the effects of cyclic AMP vary depending on the target cell.

判断题How is it that different cells can respond in different ways to exactly the same signaling molecule even when they have identical receptors

判断题There is no fundamental distinction between signaling molecules that bind to cell-surface receptors and those that bind to intracellular receptors.

判断题Water has a high specific heat.

判断题The density of water is less than the density of ice.

判断题Both the GTP-bound a subunits and nucleotide-free b complexes, but not GDP-bound, fully assembled G proteins, activate other molecules downstream of G-protein-linked receptors.