Final answer:
In an in vitro translation system using an RNA polymer made with only adenine and cytosine, all amino acids except glutamine (Gln) could be incorporated into a polypeptide because glutamine's codons (CAA and CAG) require guanine, which is absent.
Step-by-step explanation:
The student is asking about the synthesis of an RNA polymer and its subsequent use in an in vitro translation system. The RNA polymer is made by using the enzyme polynucleotide phosphorylase with equal quantities of the nucleotide diphosphates ADP (adenine) and CDP (cytosine). This experimental setup can only produce RNA polymers that contain adenine and cytosine. Since each amino acid is coded by a combination of three nucleotide bases, known as a codon, and we only have adenine and cytosine available in this RNA polymer, not all amino acids can be incorporated into a polypeptide using this RNA.
In the genetic code, the amino acid lysine (Lys) is encoded by the codons AAA and AAG. Proline (Pro) is encoded by the codons CCU, CCC, CCA, and CCG. Arginine (Arg) has codons CGU, CGC, CGA, CGG, AGA, and AGG. Asparagine (Asn) is encoded by AAU and AAC. However, glutamine (Gln) is encoded by the codons CAA and CAG. Since our RNA polymer can only be made up of adenine (A) and cytosine (C), we can synthesize codons for all the listed amino acids except glutamine, which needs the nucleotide guanine (G) that is absent in this experiment.
Therefore, when this RNA is used in an in vitro translation system, all of the following amino acids could be incorporated into a newly made polypeptide, except glutamine (Gln).