The following CSS properties will be explained: 1  color. 2  background-color. 3  background-image.  background- 1 repeat. background-attachment.  background- 1 position. background.
The transmission of a signal through the nervous system can also be considered an example of long-distance signaling. Local signaling in plants is not well understood. Because of their cell walls, plants must have different mechanisms from animals. Plants and animals use hormones for long-distance signaling. In animals, specialized endocrine cells release hormones into the circulatory system, by which they travel to target cells in other parts of the body. Plant hormones, called growth regulators, may travel in vessels but more often travel from cell to cell or move through air by diffusion.
Cells have proteins called receptors that bind to signaling molecules and initiate a physiological response. Different receptors are specific for different molecules. Dopamine receptors bind dopamine, insulin receptors bind insulin, nerve growth factor receptors bind nerve growth factor, and so on.he signal transduction cascade begins when adenylyl cyclase, a membrane-bound enzyme, is activated by G-protein molecules associated with the adrenergic receptor. Adenylyl cyclase creates multiple cyclic AMP molecules, which fan out and activate protein kinases (PKA, in this example).