We study polynomials computed by depth five circuits, i.e., polynomials of the form t i =1 Q i where Q i = r i j =1 i j d i j , i j are linear forms and r i , t 0 . These circuits are a natural generalization of the well known class of circuits and received significant attention recently. We prove exponential lower bound for the monomial x 1 x n against the following sub-classes of circuits: \begin{itemize} \item Depth four homogeneous arithmetic circuits. \item Depth five [ n ] [ 21] and [ 2 n 1000 ] [ n ] arithmetic circuits where the bottom gate is homogeneous; \end{itemize} Our results show precisely how the fan-in of the middle gates, the degree of the bottom powering gates and the homogeneity at the bottom gates play a crucial role in the computational power of circuits.