This paper proposes "Quantum-Mitochondrial Fusion" (QMF) as a hypothetical mechanism for room-temperature nuclear fusion, derived from the structural analogy of the observable universe to a scaled-up eukaryotic human cell. By inverting the mapping where stars correspond to mitochondria (both generating energy via fusion/ATP production), QMF applies cellular microtubule quantum coherence (Orch-OR-like processes) to stabilize deuterium nuclei for low-energy fusion without plasma. Mitochondria achieve ~40–60% efficiency in ATP production, surpassing current fusion reactors (~1–5% net). Conventional cold fusion claims remain controversial and unproven, but the bio-cosmic scaling (~10¹⁸–10²⁰) enables microtubule-inspired quantum beats (>100 ms coherence, Prediction 3/11) to facilitate fusion at ambient conditions. Hypothetical outputs of ~10–100 kW per kg device are calculated, with energy densities ~10⁴ times higher than solar PV (~200 W/m²). Testability ties to JWST/DESI validations of stellar formation predictions.