When is gene expression blocked in the lac operon system?

The trp operon in e. coli regulates genes that code for enzymes required for synthesis of the repressible operon. when tryptophan is not available amino acid tryptophan. the trp operon is a in the environment, the trp repressor protein activeinactiveregulated. therefore, rna polymerase can bind to the genes to begin transcription.

Aheterozygous normal male marries a woman with a sickle cell anemia. give the genotypes and possible phenotypes of the offspring

If jane has the blood type ab and marries john who has type o blood what are the possible phenotypes of their first kid?