PS04 - h can infect only one type Also phage of genotype r...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Problem Set 4 due Thursday 29 September 1. An Hfr strain transfers genes in alphabetical order. When tetracycline sensitivity is used for counterselection, the number of h+ tet-r colonies is 1000-fold lower than the number of h+ str-r colonies found when streptomycin sensitivity is used for counterselection. Suggest an explanation for the difference. 2. A lawn of E. coli bacteria, composed of two bacterial strains, is infected by phage. Phage of genotype h- can infect both strains, while phage of genotype
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: h+ can infect only one type. Also, phage of genotype r- make large plaques, while phage of genotype r+ make small plaques. Describe the different plaque morphologies in the following situations. a. Lawn is infected by r- h+ phage only. b. Lawn is infected by r- h-phage only. c. Lawn is infected by both r- h+ and r- h- phage. 3. What are similarities and differences between an F+ and an Hfr bacteria? In particular, compare and contrast the transfer of the F factor during conjugation....
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online