The shape of mitochondrial cristae influences the assembly and stability of respiratory chain supercomplexes (RCS), thereby affecting mitochondrial respiratory efficiency. This study demonstrates that cristae shape determines the formation of functional RCS, which are essential for efficient energy production. Genetic and apoptotic manipulations of cristae structure affect RCS assembly and activity, independent of changes in mitochondrial protein synthesis or outer mitochondrial membrane permeabilization. The efficiency of mitochondria-dependent cell growth depends on cristae shape, as evidenced by the impact of cristae remodeling on RCS assembly and mitochondrial function. The study shows that cristae shape is a critical factor in linking mitochondrial membrane morphology to its functional properties. The research also highlights the role of OPA1 in regulating cristae shape and RCS assembly, with implications for mitochondrial diseases. Overall, the findings suggest that cristae shape is a key determinant of mitochondrial function and respiratory efficiency.The shape of mitochondrial cristae influences the assembly and stability of respiratory chain supercomplexes (RCS), thereby affecting mitochondrial respiratory efficiency. This study demonstrates that cristae shape determines the formation of functional RCS, which are essential for efficient energy production. Genetic and apoptotic manipulations of cristae structure affect RCS assembly and activity, independent of changes in mitochondrial protein synthesis or outer mitochondrial membrane permeabilization. The efficiency of mitochondria-dependent cell growth depends on cristae shape, as evidenced by the impact of cristae remodeling on RCS assembly and mitochondrial function. The study shows that cristae shape is a critical factor in linking mitochondrial membrane morphology to its functional properties. The research also highlights the role of OPA1 in regulating cristae shape and RCS assembly, with implications for mitochondrial diseases. Overall, the findings suggest that cristae shape is a key determinant of mitochondrial function and respiratory efficiency.