Part 2: Multiple choice (2 point each/22 total points) Circle the letter indicat

Question

Part 2: Multiple choice (2 point each/22 total points) Circle the letter indicating the correct answer The table below summarizes the results of a replica-plating experiment where a mixture of 347 E. coli strains of different genotypes were tested for their ability to growth on a variety of media. Use this data to answer the following 5 questions (2.1 through 2.5).

Medium Number of colonies that grew Complete medium (contains all amino acids, vitamins, and glucose as a carbon source) 347

Minimal medium (glucose as a carbon source) 261

Minimal medium + ampicillin (an antibiotic) 51

Minimal medium + methionine (an amino acid) 303

Minimal medium + arginine (an amino acid) 301

Minimal medium +methionine +ampicillin 57

Minimal medium + arginine +ampicillin 64

Question 2.1: How many colonies are auxotrophs?

A. 347 B. 261 C. 86 D. 51 E. 44

Question 2.2: How many colonies are wild type (met+ arg+ AmpS )?

A. 51 B. 210 C. 261 D. 296 E. 347

Question 2.3: How many colonies are met- arg+ ?

A. 261 B. 303 C. 301 D. 42 E. 86

Question 2.4: How many colonies are met+ arg- ?

A. 40 B. 42 C. 86 D. 46 E. 44

Question 2.5: How many colonies are met- arg- ?

A. 2 B. 4 C. 36 D. 82 E. 86

Explanation / Answer

Solution :-

Ans 2.1 = 347

Ans 2.2 = B. 210

Ans 2.3 = C. 301

Ans 2.4 = B. 42

Ans 2.5 = B. 4

Important note :-

E. coli represents the most cost-effective and widely used host for heterologous production of foreign proteins, an efficient method to express proteins selectively labeled with isotopes would be highly valuable for these studies. However, a main drawback is misincorporation and dilution of input isotope labels to unwanted amino acid types due to metabolic scrambling in vivo.

To overcome this problem, we have generated E. coli auxotroph strains that are compatible with the widely used T7 RNA polymerase overexpression systems and that minimize metabolic scrambling. Several examples of selective amino acid isotope labeling of simple and complex proteins with bound cofactors, as an initial guide for practical applications of these E. coli strains.

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.