  In this thesis, we have studied the large scale structure and system level
dynamics of certain biological networks using tools from graph theory,
computational biology and dynamical systems. We study the structure and
dynamics of large scale metabolic networks inside three organisms, Escherichia
coli, Saccharomyces cerevisiae and Staphylococcus aureus. We also study the
dynamics of the large scale genetic network controlling E. coli metabolism. We
have tried to explain the observed system level dynamical properties of these
networks in terms of their underlying structure. Our studies of the system
level dynamics of these large scale biological networks provide a different
perspective on their functioning compared to that obtained from purely
structural studies. Our study also leads to some new insights on features such
as robustness, fragility and modularity of these large scale biological
networks. We also shed light on how different networks inside the cell such as
metabolic networks and genetic networks are interrelated to each other.
