Final answer:
Exogenous refers to a substance produced outside the body, which can be of natural or synthetic origin, and binds to transmembrane receptor proteins.
Step-by-step explanation:
The term exogenous refers to a substance that is produced outside the body. It can come from sources such as plants or laboratory processes, and binds to transmembrane receptor proteins in the body. An exogenous chemical can be of natural origin or synthetically produced in a pharmaceutical laboratory.