Based on the spectral analysis of a composite Hubble Space Telescope (HST) spectrum made of 184 quasar data, we model the emission lines of the broad-line region (BLR) using analytic functions. For simplicity of this paper we neglect effects of the continuum emission, which may be resulting from emission by the accretion disk, and assume the emission of the BLR to be composed of the most prominent emission lines that form as a result of ionization and recombination processes within regions of the BLR. We also calculate opacities for gamma-rays propagating in the BLR and interacting with the modeled emission to produce electron-positron ($e^{\pm}$) pairs.