True-breeding pea plants, one with purple, axial flowers and…

True-breeding pea plants, one with purple, axial flowers and the other with white, terminal flowers; are crossed. These genes for flower color and location assort independently and their alleles have dominant/recessive relationships. All F1 individuals (dihybrids) have purple, axial flowers indicating these are the dominant traits. Among the F2 offspring of a subsequent dihybrid cross, what is the frequency of plants with white, axial flowers?

The HIV drug, Ritonavir, is a competitive inhibitor of HIV p…

The HIV drug, Ritonavir, is a competitive inhibitor of HIV protease. One of the challenges of treating HIV is its high mutation rate, which can create resistance to available drugs. Where in the protease enzyme would amino acid changes need to take place in order to make it ineffective?