A quorum of the commission is a majority of the voting members of the commission. Any alternate member to any producer member may serve in the absence of any other member if that member’s alternate is also absent and if that action is necessary to establish a quorum. Except as provided in Sections 78214, 78231, and 78302, the vote of a majority of the members present at a meeting at which there is a quorum shall constitute the act of the commission.