week01key - Biochemistry 442, Spring 2007: Week 1 Key 1. A)...

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Biochemistry 442, Spring 2007: Week 1 Key 1. A) To translate AGC and AGU, one of the following 2 tRNAs are needed: ICU or GCU. To translate UC*, there're 3 combinations as follows: IGA+CGA, IGA+UGA or GGA+UGA. Thus, to translate all 6 condons of Ser, we could have 2*3=6 sets, as follows: ICU+IGA+CGA ICU+IGA+UGA ICU+GGA+UGA GCU+IGA+CGA GCU+IGA+UGA GCU+GGA+UGA B) One of the possible wobble tRNAs corresponds to both an Arg and Ser codon, which is ICU 2. a) 5’ CAU 3’. It pairs with the start codon 5’ AUG 3’. b ) RNA: 5’ G A A U G G G A U G U A G U A A C U A G U C 3’ DNA: 3’ C T T A C C C T A C A T C A T T G A T C A G 5’ Requested convention is 5’ to 3’: so answer is: 5’ G A C T A G T T A C T A C A T C C C A T T C 3’ c and d) c: 5’G A | A U G |G G A |U G U|A G U|A A C|U A G|U C 3’ d: 5’G A | A U G |G G A |U G U|A G U|A A C| U A G | U C 3’ There are two start codons and three stop codons in the RNA sequence, depending on the reading frame. If you use one start codon you get a polypeptide, if you use the other you immediately encounter a stop codon and don’t get a polypeptide. e) prokaryotic The mechanism of some antibiotics exploits functional and structural differences between eukaryotic and prokaryotic ribosomes, preferentially affecting bacterial ribosomes. The fact that everything stopped suggests the bar patrons are prokaryotic RNA. f) 1. Streptomycin prevents prokaryotic initiator tRNA complex from starting new polypeptides and 2. causes miscoding g) No. What makes antibiotics therapeutically valuable is their selectivity for disrupting function of prokaryotic cells preferentially to eukaryotic cells. The capability of this antibiotic to disrupt eukaryotic ribosomal function would not make it a valuable therapeutic. This one seems to preferentially disrupt eukaryotic ribosome function. This would cause toxicity/side effects in
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This test prep was uploaded on 04/07/2008 for the course BIOC 440 taught by Professor Davis during the Spring '07 term at University of Washington.

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week01key - Biochemistry 442, Spring 2007: Week 1 Key 1. A)...

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