This question combines your knowledge of conjugation (described in Chapter 7) and the genetic regulation that directs the phage λ reproductive cycles. When researchers mix donor Hfr strains with recipient F bacteria that are lysogenic for phage λ, the conjugated cells survive normally. However, if donor Hfr strains that are lysogenic for phage λ conjugate with recipient F bacteria that do not contain any phage λ, the recipient cells often lyse, due to the induction of λ into the lytic cycle. Based on your knowledge of the regulation of the two λ cycles, explain this experimental observation.