A yeast mutant with an impaired system of translocation of adenine nucleotides across the mitochondrial membrane, which stops dividing after superposition of the q- mutation, was investigated. The results of this work indicate that combination of the op1 mutation with the q- mutation in a single cell results in interruption of synthesis of polysaccharides and DNA leading to cessation of division of the op1q- mutant. The mechanism of this effect remains unclear.