Unformatted text preview: NAME: (<- 57 PERM NUMBER 4. (2.5 pts) Nine conditional lethal mutants of phage T4 are isolated and tested in pairwise,
mixed infections under non-permissive conditions for the ability to produce infective progeny. Shown below is some of the complementation results [+ = progeny phage are made]. These data
are sufﬁcient to enable completion of the table if you assume that there are no complicating factors (no deletions etc). Deductions will be made for incorrect answers (to prevent guessing). \D
as. 5. (3 pts) A cross is done between two mutant T4 phage (a + +) and (+ b c)(no order implied by
these genotypes). The genotypes of the progeny from this cross and their relative frequencies
were. a++ (28%); ab+ (1%); 4-H (7%); ++c (3%); a+c(9%); abc (9%); +b+ (11%); +bc (32%). a. What 15 the correct order of these sites a, b, and c ? \\0( WWW
b. Draw a genetic map of T4 based on these data. Show map distances ONLY for a to b and b to c. (35“? 6. (3 pits) Several mutants are isolated that are auxotrophic for tryptophan. The mutants were individually tested
for their ability to grow in the presence of compounds su5pccted to be intermediate in the biochemical pathway leading to tryptophan. Mutant I grew if Chorismate, Anthranilate, or tryptophan were added, Mutant 2 grew if
anthranilate or tryptophan were added, but not chorismate, Mnatnt 3 grew if Tryptophan was added but not chorismate or anthranilate.
a From the analysis of the. above _d_ata propose a metabolic pathway leading to Tryptophan biosynthesis and indicate which step is controlled by eac e (use a ﬂow diagram arrows, and show '
the arrows/' ' - Or it ’ ' 3
Pfecorrjrt, ﬂ Char ‘-—~% A’l/tléi #9 T‘— 7. (3 pm) A culture __of E coli 15 infected at a multiplicity of infection of 2 with phage T4. Determine the,- ﬁacti on of bacteria that wOuld receive two or mortfphage each. “-3, H __M __ _ , .
Poisson Formula: f(l)_ — em in where “m” = mean 'itumbero-f Item's andt “ ”— —frequency of the “i -l.l'l)a class. i! ...
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- Spring '08