  We report a first-principles study on the elastic, vibrational, and
electronic properties of recently synthesized phosphorene. By calculating
Gr\"uneisen parameters, we evaluate the frequency shift of Raman/infrared
active modes via symmetric biaxial strain. We also study an inducing
semiconductor-metal transition, the gap size, and effective mass of carriers in
various strain configurations. Furthermore, we unfold the emergence of a
peculiar Dirac-shaped dispersion for specific strain conditions, including the
zigzag-oriented tensile strain. The observed linear energy spectrum has
distinct velocities corresponding to each of its linear branches and is limited
to the $\Gamma-X$ direction in the first Brillouin zone.
