Answer:
the binding of a chemical messenger activating a cytoplasmic enzyme, such as kinase, that leads to specific cellular responses.
Explanation:
A living organism has several chemical messengers that are molecules capable of binding enzymes, adjusting their active site and activating them, allowing them to establish key-lock relationships with other molecules, catalyzing them and forming new biological products that will be used in the various metabolic reactions of the organism, leading to specific cellular responses.