Open QuestionSeveral lines of experimental evidence pointed to a triplet genetic code. Identify three pieces of information that supported the triplet hypothesis of genetic code structure.
Open QuestionAssuming the genetic code is a triplet, what effect would the addition or loss of two nucleotides have on the reading frame? The addition or loss of three, six, or nine nucleotides?
Open QuestionThe mRNA formed from the repeating tetranucleotide UUAC incorporates only three amino acids, but the use of UAUC incorporates four amino acids. Why?
Open QuestionA portion of a DNA template strand has the base sequence 5′-...ACGCGATGCGTGATGTATAGAGCT...-3′Which is the third amino acid added to the polypeptide chain?
Open QuestionIn studies using repeating copolymers, AC . . . incorporates threonine and histidine, and CAACAA . . . incorporates glutamine, asparagine, and threonine. What triplet code can definitely be assigned to threonine?
Open QuestionWhat are the differences between the universal code and that found in the mitochondria of some species? Given that some changes (UGA =stop→Trp) have occurred multiple independent times in evolution, can you think of any selective advantage to the mitochondrial code?
Open QuestionIn a coding experiment using repeating copolymers (as demonstrated in Table 13.3), the following data were obtained:Copolymer Codons Produced Amino Acids in PolypeptideAG AGA, GAG Arg, GluAAG AGA, AAG, GAA Lys, Arg, GluAGG is known to code for arginine. Taking into account the wobble hypothesis, assign each of the four codons produced in the experiment to its correct amino acid.
Open QuestionIn 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.