Except as otherwise authorized in this section and section 108.05 of the Revised Code, each officer whose office is created by sections 121.02, 121.04, and 121.05 of the Revised Code shall devote the entire amount of time for which he receives compensation from that office to the duties of the office, and shall hold no other office or position of profit. Such an officer is entitled to his actual and necessary expenses incurred in the performance of his official duties, and may serve as a member of any board or commission to which he is appointed by the governor. Any such officer who serves as a member of a board or commission is entitled to his actual and necessary expenses incurred in the performance of his official duties as a member, but shall receive no other compensation for that service.