(1) A physician assistant is professionally and legally responsible for the care and treatment of a patient by a physician assistant licensed in accordance with this chapter. (2) A physician assistant may: (a) diagnose, examine, and treat human conditions, ailments, diseases, injuries, or infirmities, either physical or mental, by any means, method, device, or instrumentality; (b) obtain informed consent; (c) supervise, delegate, and assign therapeutic and diagnostic measures; (d) certify the health or disability of a patient as required by any local, state, or federal program; and (e) authenticate any document that a physician may authenticate.