Final answer:
A cytoplasmic protein with many tyrosines is likely to interact with another protein molecule, not DNA, RNA, or lipids. In an experiment similar to Nirenberg and Matthaei's, adding RNA with only cytosine would produce a polypeptide chain of proline, as the CCC codon for proline would match the cytosine-only RNA sequence.
Step-by-step explanation:
The presence of many regions containing the amino acid tyrosine in a novel cytoplasmic protein suggests that this protein may interact with a protein molecule. Tyrosine is often involved in protein-protein interactions, especially when it comes to signal transduction pathways where tyrosine can be phosphorylated by kinases, thereby changing the function or interaction of the protein. This structural feature doesn't imply direct interactions with DNA, RNA, or lipid molecules, which often requires specific binding domains or motifs not indicated by the presence of tyrosine alone.
Continuing with the experiment similar to Nirenberg and Matthaei, if you added synthetic RNA containing only the base cytosine, a polypeptide chain consisting of proline would be produced. This is because the codon CCC (formed from three cytosine bases) codes for the amino acid proline. Every tRNA molecule that can bind to this codon through its anticodon will carry proline, hence a polypeptide consisting solely of this amino acid will be synthesized.