Controls uses inappropriate methodology or does

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controls, uses inappropriate methodology or does indicate methodology used, or doesn’t explain how data supports hypothesis. E.g. “Control: Teicoplanin resistant S. haemolyticus isolated from factory, teicoplanin- sensitive S. aureus (isolated from external source). Exp: Teicoplanin resistant S. aureus isolated from factory. Extract DNA genome from all subjects. Examine entire genome for the vraS gene on all controls and the experimental. If the hypothesis is true, the control S. aureus won’t have the vraS gene while the S. haemolyticus and resistant S. aureus will.”
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NAME _________________________ SID#___________________________ Discussion Section: _______________ 3 4 Student does two of the improper things from 5 point answer. E.g. “Perform DNA fingerprinting on the isolated strain of S. aureus that is resistant to teicoplanin, a strain of S. haemolyticus that is teicoplanin resistant, and the vraS gene itself. You would expect to see the vraS bands in both of the other fingerprints if the hypothesis is correct.” 3 Students does not identify the need to assess the presence of the varS gene in the Tel R S. aureus strain from the factory, but does show some understanding how that one would compared genomes to identify mechanism of resistance. E.g. “1) Incubate strain of S. aureus and antibiotic teicoplanin together. 2) Streak purify on agar plate for surviving bacteria. 3) Incubate surviving strain with antibiotic teicoplanin. 4) Streak purify on agar plate for surviving bacteria. 5) Repeat one more time the process above to make sure the strain is resistant to the antibiotic. 6) Sequence the last surviving strain and see if the genome is similar to the teicoplanin resistant S. haemolyticus.” 2. The figure shows the results of an in vitro transcription assay of the ribD gene. This assay was performed in the presence and absence of a small molecule, FMNH 2 , and a protein RibR. Two ribD transcripts were observed. There is more of the lower band in lane 2 than lane 1, and none of the lower band in lane 3. A) From this data, what conclusion can you draw about how FMNH 2 controls ribD expression? (2.5 points) 2.5 Student identifies that ribD is controlled by attenuation and that FMNH 2 acts through a possible riboswitch. E.g.“FMNH 2 leads to more production of short mRNA fragments which indicate attenuation of transcription. Therefore FMNH 2 could possibly bind to the 5’ untranslated region and create a terminator structure.” 2 Only recognizes that attenuation occurs but not how attenuation could be simulated. E.g “In the presence of only FMNH2 it inhibits expression causing attenuation.” 1.5 Student identifies attenuation occurs or a riboswitch is present, but also demonstrates a significant misunderstanding of how these processes work. E.g. “FMNH2 gene causes termination of translation, mRNA product is short. May be riboswitch.” FMNH 2 RibR 3
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NAME _________________________ SID#___________________________ Discussion Section: _______________ 4 1 Students directly interprets the data as a simple increase in transcription, but fails to interpret the significance of two different sized transcripts for ribD.
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  • Fall '19
  • DNA, RNA, Student Identification Number, ssRNA

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