Glycine (Gly) serves as an ideal model to study the chemical evolution and increasing molecular complexity in interstellar and planetary environments. On one hand, Glycine stands out due to its greater complexity compared with standard interstellar complex organic molecules (iCOMs, e.g., NH2CHO), marking a significant step in chemical formation and transformation processes. Despite this, the direct detection of glycine in the interstellar medium remains unconfirmed. On the other hand, Gly is the simplest proteinaceous amino acid and, accordingly, is a crucial molecular building block, essential for understanding how biomolecules react and condense to form biopolymers. The pathway of Gly can be elucidated by integrating results from various investigative approaches. Experimental evidence shows that glycine can be synthesized in laboratories under conditions simulating interstellar environments (e.g., UV irradiation of IS ice analogues). Glycine has been detected in comets (81P/Wild and 67P) as well as in numerous carbonaceous chondrite (CC) meteorites (e.g., Murchison). Additionally, experiments have demonstrated that glycine can polymerize in the presence of naturally occurring minerals. In this contribution, we offer an atomistic interpretation of Gly’s life pathway through a quantum mechanical modelling approach, deriving the mechanistic steps and related energetics for: (i) its formation from simple raw materials available in the interstellar medium, (ii) its interaction, retention, and protection by cometary and meteoritic materials, and (iii) its polymerization catalysed by mineral surfaces likely present in rocky planetary crusts.