Question

QUESTION 1 Imagine you are preparing an industrial enzyme assay. The protocol says to add 20 mL of 100 mM NaCl to your assay, and the final volume of the assay is 100 ml. What is the working concentration of NaCl? The number of significant digits you include in your answer doesn't matter, but it must be in units of mM. QUESTION 2 Imagine you are preparing an enzyme assay that requires a working concentration of 10 mM NaCl. If the concentration of NaCl in your stock solution is 500 mM and the final volume of the assay is 50 L, how much of the NaCl stock solution do you need to add to the assay? Enter the number only for units of uL. The number of significant digits you include in your answer doesn't matter. QUESTION 3 Which of the following A260:A280 ratios tells us that our sample is relatively pure? O 1.4 O 0.5 1.9 2.4 QUESTION 4 Which of the following correctly describes an auxotroph? A medium lacking a nutrient needed for a specific strain of an organism such as a bacterium to grow. A medium containing all the nutrients needed for an organism such as a bacterium to grow. A strain lacking the ability to synthesize one or more nutrients. O A nutrient needed for an organism such as a bacterium to grow.