A mutant bacterial cell has a defective aminoacyl- tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. What would the consequence of this be for the cell?
A) None of the proteins in the cell will contain phenylalanine.
B) The ribosome will skip a codon every time a UUU is encountered.
C) The cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine- specifying anticodons.
D) Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.
E) The ribosome will stall whenever an abnormal lysine tRNA binds to the A site.

Question

Quizplus · Accepted Answer

The mutant bacterial cell will attach lysine instead of phenylalanine to tRNAs with the anticodon AAA. When the ribosome encounters the codon UUU, it will pair it with the anticodon AAA carrying lysine instead of phenylalanine. As a result, proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. This could potentially alter the structure and function of the resulting proteins.

A Mutant Bacterial Cell Has a Defective Aminoacyl- TRNA Synthetase