  Chemical composition of a molecular cloud is highly sensitive to the physical
properties of the cloud. In order to obtain the chemical composition around a
star forming region, we carry out a two dimensional hydrodynamical simulation
of the collapsing phase of a proto-star. A total variation diminishing scheme
(TVD) is used to solve the set of equations governing hydrodynamics. This
hydrodynamic code is capable of mimicking evolution of the physical properties
during the formation of a proto-star. We couple our reasonably large gas-grain
chemical network to study the chemical evolution during the collapsing phase of
a proto-star. To have a realistic estimate of the abundances of bio-molecules
in the interstellar medium, we include the recently calculated rate
coefficients for the formation of several interstellar bio-molecules into our
gas phase network. Chemical evolution is studied in detail by keeping grain at
the constant temperature throughout the simulation as well as by using the
temperature variation obtained from the hydrodynamical model. By considering a
large gas-grain network with the sophisticated hydrodynamic model more
realistic abundances are predicted. We find that the chemical composition are
highly sensitive to the dynamic behavior of the collapsing cloud, specifically
on the density and temperature distribution.
