In the yeast Saccharomyces cerevisiae, inactivation of the gene encoding the  subunit of the ATP synthase led to a lack of assembly of the catalytic sector. In addition a slow‐growth phenotype was observed on fermentable medium. This alteration appears in strains lacking intact mitochondrial DNA and showing a defect in the assembly of the catalytic sector, such as the yeast strain inactivated in the gene encoding the ε subunit. In rho− mitochondria having an intact F1, the ion movement resulting from the exchange of ADP formed in the organelle and ATP entering the mitochondrial compartment led to a mitochondrial transmembranous potential Ψ that was sensitive to carboxyactractyloside. This ion movement was dramatically decreased in rho− mitochondria lacking the  subunit and thus the F1 sector, whereas a cell devoid of  subunit and complemented with a plasmid harboring the ATP gene displayed an assembled F1, a normal generation time and a fully restored mitochondrial potential. This result could be linked to the involvement of the membrane potential Ψ which is indispensible for mitochondrial biogenesis.