a. This chapter shall apply to heads of agencies holding office upon appointment of the mayor and to heads of those units within the executive office of the mayor designated by the mayor to be covered by the provisions of the chapter. It shall not apply to agencies headed by boards, commissions, or other multi-member bodies whether appointed by the mayor or otherwise, nor to elected officials, nor to other agencies the heads of which are appointed by officials other than the mayor or by multi-member bodies. References in this chapter to other sections of the charter shall not be construed to affect the applicability of those sections to officials and agencies not subject to this chapter.
b. Except as otherwise provided by law, all functions, powers and duties assigned to each mayoral agency by the charter or other law shall be vested in the head of such agency. In exercising such powers and duties and the powers and duties specifically assigned to the agency head, such official shall exercise due diligence in ensuring their faithful execution, enforcement and performance. In addition to the powers and duties granted to them and their agencies by the charter or by other law, and in addition to such other functions as are assigned to them by the mayor, heads of mayoral agencies shall have the powers and duties listed in the remaining sections of this chapter.