In the absence of tryptophan and the trpD structural gene contains a frameshift insertion mutation, the structural genes will: [ Select ] ["No longer be expressed", "Be constantly expressed but the protein will be truncated and possibly non-functional", "Be constantly expressed but the protein will be longer and possibly non-functional"] In the presence of tryptophan and the trpD structural gene contains a frameshift insertion mutation, the structural genes will: [ Select ] ["No longer be expressed", "Be constantly expressed but the protein will be truncated and possibly non-functional", "Be constantly expressed but the protein will be longer and possibly non-functional"]

In the trp operon, if a mutation occurred in the gene for the repressor so that it could bind to the operator even in the absence of tryptophan____________. a) the inducer cannot bind trpO, so operon gene transcription occurs b) the active repressor cannot bind trpO, so operon gene transcription is attenuated c)the active repressor binds tpO, so operon gene transcription is always repressed d) the repressor binds the corepressor, and operon gene transcription occurs.

Describe what would happen to the lac operon in a low-lactose environment and in a high lactose environment. a) How will each of these environments affect gene expression? b) What would happen to the repressor in each case? c) How will each of these environments affect RNA polymerase?

You plan to synthesize a peptide to be used as a vaccine to treat melanoma, a particularly aggressive form of skin cancer. Normally, gp100, a protein on the surface of melanocytes, activates cell growth when it is bound by its ligand. Activation of the growth pathway depends on the presence of threonine in the ligand. The effective peptide vaccine will mimic the natural ligand, but won’t cause cell growth and division. Below is the sequence of the natural ligand:   LDMKTAG   In order to ensure your newly designed peptide vaccine does not cause cell growth upon binding, you must substitute the Threonine residue at position 5. What amino acid would you replace it with, bearing in mind that the peptide should still be similar enough to bind to the gp100 protein in the surface of melanocytes. Explain your choice. Your vaccine will be administered as a topical cream, and you require your peptide to have an overall neutral charge in order to be functional. At what pH should you formulate…