Section 385. Heads of mayoral agencies

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.