Question

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

Answer 1

Answer:

The correct answer is A) Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.

Explanation:

If a mutation occurs in the bacterial cell that produces aminoacyl tRNA synthetase that attaches a lysine instead of normal phenylalanine than during the translation process when this tRNA will come opposite to its complementary codon sequence i.e. UUU it will add lysine in place of phenylalanine.

Therefore where ever in the mRNA the UUU codon would be present the mutated tRNA having anticodon AAA bounded with lysine residue will be added. As a result, the protein will include lysine amino acid residue in place of phenylalanine. So the correct answer is A.