![Biochemistry: Concepts and Connections (2nd Edition)](https://www.bartleby.com/isbn_cover_images/9780134641621/9780134641621_largeCoverImage.gif)
Concept explainers
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?
![Check Mark](/static/check-mark.png)
Trending nowThis is a popular solution!
Learn your wayIncludes step-by-step video
![Blurred answer](/static/blurred-answer.jpg)
Chapter 19 Solutions
Biochemistry: Concepts and Connections (2nd Edition)
Additional Science Textbook Solutions
Fundamentals of General, Organic, and Biological Chemistry (8th Edition)
General Chemistry: Principles and Modern Applications (11th Edition)
Brock Biology of Microorganisms (14th Edition)
Campbell Biology: Concepts & Connections (9th Edition)
Chemistry: A Molecular Approach (4th Edition)
Microbiology with Diseases by Taxonomy (5th Edition)
- You have an extract of BL21(DE3) cells containing a soluble, 75 kDa recombinant protein that has a histidine tail at its C-terminus. This extract is still in raw form and you need to purify this protein without losing its solubility. Check the option below that represents the best purification methodology in the order of execution. * a) (1) isoelectric precipitation; (2) microfiltration; (3) affinity chromatography; (4) anion exchange chromatography b) (1) centrifugation; (2) microfiltration; (3) isoelectric precipitation; (4) affinity chromatography c) (1) centrifugation; (2) microfiltration; (3) affinity chromatography; (4) ultrafiltration d) (1) microfiltration; (2) jumping out; (3) centrifugation; (4) affinity chromatographyarrow_forwardCTP synthetase catalyzes the glutamine-dependent conversion of UTP to CTP. The enzyme is allosterically inhibited by the product, CTP. Mamma- lian cells defective in this allosteric inhibition are found to have a complex phenotype: They require thymidine in the growth medium, they have unbal- anced nucleotide pools, and they have an elevated spontaneous mutation rate. Explain the likely basis for these observations.arrow_forwardConsider the biochemical pathway shown here. Suppose that a strain of bacteria must synthesize compound 4 to survive and divide. Successful survival and division of bacteria is observed as growth of colonies on an agar plate. This strain of bacteria can grow colonies on minimal medium as long as it is supplemented with compound 1. You are in a lab that has isolated several mutants of this strain. You find that these mutants cannot grow on minimal medium supplemented with compound 1, though they can grow colonies if supplemented with compound 4. Considering what you know about the Beadle-Tatum experiments, which of the following statements would be one that should be true?arrow_forward
- You generate mutants in the metabolic pathway for starlase. You conduct some complementation tests (after testing for dominance of course) and come up with the following results: 1 2 4 6 1 + + + 2 + 3 + 4 + 5 6 a. How many complementation groups are there? [Select] b. You conduct some additional experiments to elucidate the starlase metabolic pathway. Your results are shown below. Use this information alongside information from the complementation table above to place the intermediates in the correct order on the pathway. (HINT: use the complementation groups from the table above to help you consolidate information on the tables below. Reference practice question 3 from today's lecture for help). Addition to minimal medium Mutant None starlase P 1 + + 2 + + 4 + + 5 + 6 Precursor --> [ Select ] [ Select ] [ Select ] --> starlase c. Mutant 4 has a loss-of-function mutation for which enzyme in the starlase synthesis pathway? [ Select ] E1 E2 ЕЗ Е4 Precursor > Intermediate 1→ Intermediate…arrow_forwardThe enzyme glucose oxidase isolated from the mold Penicillium notatum catalyzes the oxidation of B-D-glucose to D-glucono-6-lactone. The enzyme is highly specific for the B anomer of glucose and does not affect the a anomer. In spite of this specificity, the reaction catalyzed by glucose oxidase is commonly used in a clinical assay for total blood glucose -that is, for solutions consisting of a mixture of B- and a-D-glucose, as well as other sugars present in blood. The oxidation proceeds in the presence of oxygen and forms hydrogen peroxide, in addition to the lactone. A second enzyme, called peroxidase, catalyzes the reaction of hydrogen peroxide with colorless compounds to create a colored product, which is quantified with a simple spectrophotometer. What are the circumstances required to make this possible? Aside from allowing the detection of smaller quantities of glucose, what advantage does glucose oxidase offer over the Fehling's reagent for measuring blood glucose?arrow_forwardA number of auxotrophic mutant strains were isolated from wild-type haploid Neurospora crassa. These strains responded to the addition of certain nutritional supplements to minimal culture medium either by growth (+) or no growth (0) The data from this experiment are presented in the table below. Diagram a biochemical pathway, complete with positions of intermediates, that is consistent with the data. Indicate where in the pathway each mutant strain is blocked.arrow_forward
- What is the attached enzyme in this assay and its corresponding substrate? A. Horseradish peroxidase and OPD (o-phenylenediamine dihydrochloride) B. Horseradish peroxidase and PNPP (p-Nitrophenyl Phosphate, Disodium Salt) C. Horseradish peroxidase and TMB (3,3',5,5'-tetramethylbenzidine) D. Horseradish peroxidase and ABTS (2,2'-azinobis-3-ethylbenzothiazoleine-6- sulfonic acid)arrow_forwardAssume that a series of compounds has been discovered in Neurospora. Compounds A–F appear to be intermediates in a biochemical pathway. Conversion of one intermediate to the next is controlled by enzymes that are encoded by genes. Several mutations in these genes have been identified and Neurospora strains 1–4 each contain a single mutation. Strains 1–4 are grown on minimal media supplemented with one of the compounds A–F. The ability of each strain to grow when supplemented with different compounds is shown in the table (+ = growth; o = no growth). Which biochemical pathway fits the data presented? Media Supplement Strain A B C D E F 1 o o o + + + 2 o o o o + + 3 o o o o + o 4 o o + + + + A) A → B → C → D → E → F B) A → B → C → F → D → E C) F → B → C → D → A → E D) A → B → C → D → F → E E) A → B → F → E → C → Darrow_forwardSelect all that apply from the following to each transformation process : The following are White non-glowing colonies White glowing colonies Blue non-glowing colonies Blue glowing colonies None of the above The transformation are: a. LB + kanamycin plates that have been spread with the E. coli cells transformed with your ligations, what phenotype of the colonies do you expect to obtain . b. LB + kanamycin plates that have been spread with the E. coli cells transformed with water, what phenotype of the colonies do you expect to obtain. c. LB plates that have been spread with the E. coli cells transformed with your pHSG298, what phenotype of the colonies do you expect to obtain. d. LB + kanamycin plates that have been spread with the E. coli cells transformed with PHSG298, what phenotype of the colonies do you expect to obtain. e. LB plates that have been spread with the E. coli cells transformed with your ligations, what phenotype of the colonies do you expect to obtain. f. LB plates…arrow_forward
- Various antimicrobial drugs to treat microbial infection have diverse mechanism of action. Consider the following antimicrobial drugs: A. Seconeolitsine, known as DNA topoisomerase I inhibitor in bacteria. (i) Explain briefly how inhibiting DNA topoisomerase I is a good mechanism of action for an antibiotic, include possible molecular machineries being targeted. (ii) What would be an appropriate response if seconeolitsine works well by stating the state of supercoiling in bacteria. (iii) To prove your answer (ii), you test the condition of bacterial DNA by running gel electrophoresis, one has been treated with seconeolitsine (+ sample) and the other one is not (- sample). Explain the position of each + sample and – sample band on the gel in reference to the point of origin (where you load your samples) or how far each DNA sample travel across agarose gel. (iv) Explain why you would expect answer (iii) for each + sample and – sample. B.…arrow_forwardWhat is the purpose of Southern's blotting technique? Explain in detail the biochemical principle that underpin each step of the method.arrow_forwardPyridoxal phosphate (PLP) is a coenzyme for the enzyme ornithine aminotransferase. The enzyme was purified from cells grow in PLP = deficient media as well as from cells grown in media that contained pyridoxal phosphate. The stability of the two different enzyme preparations was then measured by incubating the enzyme at 37°C for different lengths of time and then assaying for the amount of enzyme activity remaining. The following results were obtained. (a) Why does the amount of active enzyme decrease with the time of incubation? (b) Why does the amount of enzyme from the PLP deficient cells decline more rapidly?arrow_forward
- BiochemistryBiochemistryISBN:9781319114671Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.Publisher:W. H. FreemanLehninger Principles of BiochemistryBiochemistryISBN:9781464126116Author:David L. Nelson, Michael M. CoxPublisher:W. H. FreemanFundamentals of Biochemistry: Life at the Molecul...BiochemistryISBN:9781118918401Author:Donald Voet, Judith G. Voet, Charlotte W. PrattPublisher:WILEY
- BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage LearningBiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage LearningFundamentals of General, Organic, and Biological ...BiochemistryISBN:9780134015187Author:John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. PetersonPublisher:PEARSON
![Text book image](https://www.bartleby.com/isbn_cover_images/9781319114671/9781319114671_smallCoverImage.jpg)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781464126116/9781464126116_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781118918401/9781118918401_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305961135/9781305961135_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305577206/9781305577206_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9780134015187/9780134015187_smallCoverImage.gif)