In the experiments by Benzer and colleagues, the cysteine in a cys-tRNA molecule was converted into alanine.Suppose, instead, that the cysteine had appeared in the synthesized protein where it normally does.The most likely conclusion would have been that the protein synthesis system
A) recognized tRNAs.
B) recognized amino acids.
C) recognized mRNAs.
D) was redundant but not ambiguous.
E) was ambiguous but not redundant.

Question

Quizplus · Accepted Answer

If the cysteine had appeared in the synthesized protein where it normally does, it would indicate that the protein synthesis system recognized amino acids. This is because the attachment of cysteine to the appropriate tRNA is controlled by the recognition of the amino acid by the appropriate aminoacyl-tRNA synthetase enzyme. The tRNA molecules themselves do not determine which amino acid is attached to them. Therefore, if cysteine appeared in its normal position, it would imply that the aminoacyl-tRNA synthetase recognized cysteine and attached it to the appropriate tRNA, which was then used during protein synthesis.

In the Experiments by Benzer and Colleagues, the Cysteine in a Cys-TRNA