Biochemistry: Concepts and Connections
1st Edition
ISBN: 9780321839923
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
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Chapter 19, Problem 8P
A classic way to isolate thymidylate synthase—negative mutants of bacteria is to treat a growing culture with thymidine and trimethoprim. Most of the cells are killed, and the survivors are greatly enriched in thymidylate synthase—negative mutants.
a. What
b. What is the biochemical rationale for the selection? (That is, why are the mutants not killed under these conditions?)
c. How would the procedure need to be modified to select mammalian cell mutants defective in thymidylate synthase?
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A classic way to isolate thymidylate synthase-negative mutants of
bacteria is to treat a growing culture with thymidine and trimetho-
prim. Most of the cells are killed, and the survivors are greatly
enriched in thymidylate synthase-negative mutants.
(a) What phenotype would allow you to identify these mutants?
(b) What is the biochemical rationale for the selection? (That is, why
are the mutants not killed under these conditions?)
(c) How would the procedure need to be modified to select mam-
malian cell mutants defective in thymidylate synthase?
A classic way to isolate thymidylate synthase–negative mutants of bacteriais to treat a growing culture with thymidine and trimethoprim. Most ofthe cells are killed, and the survivors are greatly enriched in thymidylatesynthase–negative mutants.(a) What phenotype would allow you to identify these mutants?(b) What is the biochemical rationale for the selection? (That is, why are themutants not killed under these conditions?)(c) How would the procedure need to be modified to select mammalian cellmutants defective in thymidylate synthase?
Compounds A, B, C, and D are known to be intermediates in the pathway for production of protein E. To determine where the block in protein-E production occurred in each individual, the various intermediates were given to each individual’s cell in culture. After a few weeks of growth with the intermediate, the cells were assayed for the production of protein E. The results for each individual’s cells are given in the following table. A plus sign means that the protein E was produced after the cells were given the intermediate listed at the top of the column. A minus sign means that the cells still could not produce protein E even after being exposed to the intermediate at the top of the column.
a) If an individual who is homozygous for the mutation found in individual 2 and heterozygous for the mutation found in individual 4 mates with an individual who is homozygous for the mutation found in individual 4 and heterozygous for the mutation found in individual 2, what could the…
Chapter 19 Solutions
Biochemistry: Concepts and Connections
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