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.hosphate groups can be added to multiple sites in a single protein, and a single protein may in turn be the substrate for multiple kinases and phosphatases. At any one time, a cell is receiving and responding to numerous signals, and multiple signal transduction pathways are operating in its cytoplasm.
Definition of macropore. : a pore (as in coal) of comparatively large size; especially : a pore in soil of such size that water drains from it by gravity and is not held by capillary action.
In certain species of diatoms, auxospores are specialised cells that are produced at key stages in their cell cycle or life history. Auxospores typically play a role in growth processes, sexual reproduction or dormancy. Auxospores are involved in re-establishing the normal size in diatoms because successive mitotic cell divisions leads to a decrease in cell size.