Essentials of Genetics 9th Edition by Michael Palladino William Klug, Michael Cummings, Charlotte Spencer

Exercise 1

In this chapter, we focused on the genetic code and the transcription of genetic information stored in DNA into complementary RNA molecules. Along the way, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions:
(a) How did we determine the compositions of codons encoding specific amino acids?
(b) How were the specific sequences of triplet codes determined experimentally?
(c) How were the experimentally derived triplet codon assignments verified in studies using bacteriophage MS2?
(d) How do we know that mRNA exists and serves as an intermediate between information encoded in DNA and its concomitant gene product?
(e) How do we know that the initial transcript of a eukaryotic gene contains noncoding sequences that must be removed before accurate translation into proteins can occur?