9 Random copolymers were used in some of the experiments that revealed the characteristics of the genetic code. For each of the following ribonucleotide mixtures, give the expected codons and their frequencies, and give the expected proportions of the amino acids that would be found in a polypeptide directed by the copolymer in a cell-free protein-synthesizing system: a. 4a: 6c
b. 4G: 1C
c. 1A: 3U: 1C
d. 1A: 1U: 1C: 1G