NS FL8 B/B Q25

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NS FL8 B/B Q25

Post by wh816 » Sat May 16, 2020 2:45 pm

I am having a difficult time understanding how there are 2 for RNCs and 1 for released protein. I found this passage to be quite difficult to grasp.
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Re: NS FL8 B/B Q25

Post by NS_Tutor_Yuqi » Mon Jun 01, 2020 12:58 am

The wording of this question is tricky, but it is essentially asking you to evaluate the ratio of the peaks in Figure 2. The passage right above the figure states that "To separate the resulting RNCs from released flavodoxin protein (FP), size-exclusion chromatography was employed, and the absorbance ratio at 260 nm (A260) vs 280 nm (A280) of the eluents enabled distinction between RNC- and FP-containing fractions (Figure 2)." From this, we can gather that we should compare the peaks for both RNC and FP between 260 and 280 nm. The first peak on the left is the elution profile of FL-RNC. The light color is 260 nm, while the dark color is 280 nm. You can see that the ratio of A260/A280 is approximately 2:1, or just 2. However, when you look to the peak on the right, which is FL-FP, the light and dark colored peaks are approximately the same, which means that their ratio is 1:1, or just 1. This is how you arrive at answer choice A.
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