Disclosed are novel acyl-CoA synthetases and novel acyltransferases, nucleic acid molecules encoding the same, recombinant nucleic acid molecules and recombinant host cells comprising such nucleic acid molecules, genetically modified organisms (microorganisms and plants) comprising the same, and methods of making and using the same. Also disclosed are genetically modified organisms (e.g., plants, microorganisms) that have been genetically modified to express a PKS-like system for the production of PUFAs (a PUFA PKS system or PUFA synthase), wherein the organisms have been modified to express an acyl-CoA synthetase, to express an acyl transferase, to delete or inactivate a fatty acid synthase (FAS) expressed by the organism, to reduce competition for malonyl CoA with the PUFA synthase or to increase the level of malonyl CoA in the plant or plant cell, and in one aspect, to inhibit KASII or KASIII. Additional modifications, and methods to make and use such organisms, in addition to PUFAs and oils obtained from such organisms, are disclosed, alone with various products including such PUFAs and oils.