Quantum biology is an emerging interdisciplinary field that investigates the fundamental quantum mechanisms underlying biological processes and their potential roles in the emergence and sustainability of life beyond Earth. While classical biochemistry successfully describes many aspects of life, experimental and theoretical evidence increasingly suggests that quantum effects such as coherence, tunneling, and entanglement play crucial roles in processes such as photosynthesis, enzyme catalysis, olfaction, and magnetoreception. In photosynthesis, energy transfer occurs through quantum coherence in pigment–protein complexes, while enzyme catalysis can involve proton or electron tunneling. Olfactory sensing may rely on electron tunneling, and magnetoreception in birds involves spin dynamics and entanglement in cryptochrome proteins. This work provides an in-depth analysis of these mechanisms, emphasizing how they might operate under cosmic conditions, including extreme temperatures, high-radiation, microgravity, and low-energy environments. Understanding these processes offers insights into the limits of quantum coherence in extreme environments, the potential emergence of life in diverse planetary and interstellar settings, and the fundamental principles governing complex systems. Additionally, potential applications in quantum-inspired technologies and biomimetic systems are discussed, highlighting how principles observed in living organisms can guide the design of novel quantum devices. By examining quantum mechanisms in both terrestrial and cosmic contexts, this work bridges physics, biology, and astrobiology, emphasizing the universal relevance of quantum principles to life across the cosmos.