The ilv-leu operon of bacillus subtilis comprises seven genes necessary for the biosynthesis of isoleucine, valine, and leucine. the structural genes of this operon are transcribed when these amino acids are deficient in the cell. the vana operon codes enzymes that modify the binding targets of antibiotic vancomycin and therefore give antibiotic resistance to the bacteria. the structural genes of this operon are transcribed when the antibiotic vancomycin is present in the environment. the ilv-leu operon is operon, and the vana operon is operon.

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.