(3) You are in charge of an epidemiological investigation involving the outbreak
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Question
(3) You are in charge of an epidemiological investigation involving the outbreak of a new virus. The viral isolates have had the genomic material isolated and you are now trying to determine what type of virus it is in the field. You only have access to a UV-VIS spectrophotometer on location so you dilute the viral nucleic acid sample to 25mM and measure it in the spectrophotometer. The A260 measurement on the spectrophotometer is 0.825. What type of genome does this virus contain based upon the molar absorptivities below? 1. SSRNA (40 cmM) 2. dsRNA (23 cm 1M) 3. ssDNA (50 cm-1M) 4. dsDNA(33 cm 1M) (4) You have to identify which of the following proteins (subjected to trypsin digestion) represent the peptide fragment mass spectrum shown on the image below? i. Protein A GLAQYMMKTDRISTHWEGKIENPWCKEMEONYIEKPCGRERWNVFDPPSRHTETCFMNHKYNPYCCVFA li. Protein B GLHCKEMEQNYIEKPCGRERWNVKYNPYCCVFAAFDPPSRHTETCFMNOYMMKTDRISTHWEGKIENPW ii. Protein C TDRISTHWEGKIEAFNPWEREMEONYIEKPCGRKWNVKYNPYCCVFADPPSRHTETCFMNQYMMGLHCK iv. Protein D AFNPWERWNVKYNPYCCVFADPPSRHTETCFMNQYMMGLHCKEMEQNYIEKPCGRKTDRISTHWEGKIE 2.5 1.5 0.5 (5) If there was a 2:1:1 ratio of proteins A, B, and C from question 4, what would the peptide mass spectrum look like?Explanation / Answer
Answer to the first question (3):
Using Beer-Lambert law, Absorbance = molar absorptivity x molar concentration x path length.
Here, 8.825 = molar absorptivity x 0.025 M x 1 cm
or molar absorptivity = 8.825/0.025 = 33 M-1cm-1.
Hence, the correct option will be 4. dsDNA.
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