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08:26
06:38Predict the amino acid sequence produced during translation by the following short hypothetical mRNA sequences (note that the second sequence was formed from the first by a deletion of only one nucleotide):
Sequence 1: 5'-AUGCCGGAUUAUAGUUGA-3'
Sequence 2: 5'-AUGCCGGAUUAAGUUGA-3'
What type of mutation gave rise to sequence 2?
In the triplet binding technique, radioactivity remains on the filter when the amino acid corresponding to the codon is labeled. Explain the rationale for this technique.
When the amino acid sequences of insulin isolated from different organisms were determined, differences were noted. For example, alanine was substituted for threonine, serine for glycine, and valine for isoleucine at corresponding positions in the protein. List the single-base changes that could occur in codons of the genetic code to produce these amino acid changes.
In studies of the amino acid sequence of wild-type and mutant forms of tryptophan synthetase in E. coli, the following changes have been observed:
Determine a set of triplet codes in which only a single-nucleotide change produces each amino acid change.
Refer to Table 13.1. Can you hypothesize why a synthetic RNA composed of a mixture of poly U poly A would not stimulate incorporation of ¹⁴C-phenylalanine into protein?
A short RNA molecule was isolated that demonstrated a hyperchromic shift, indicating secondary structure. Its sequence was determined to be
5'-AGGCGCCGACUCUACU-3'
Propose a two-dimensional model for this molecule.
