Molecular Biology Module 4: Translation

The alanine aminoacyl tRNA synthetase enzyme of E. coli recognizes the alanine tRNA only by an unusual G:U base pair at position 70 in the stem of the tRNA. In the laboratory, you make a copy of the alanine tRNA gene that is identical to the wildtype copy except that the anicodon sequence 5' - IGC -3' is replaced with the sequence 5' - UCA -3'. You then add this mutant tRNA gene back into a wildtype E. coli. As a result,

	1. nothing will change because the mutant tRNA will not function.
	2. all alanines in newly synthesized proteins will be replaced with serine.
	3. proteins will be truncated randomly at different alanine positions.
	4. some proteins will be longer than ususal.
	5. all proteins will be truncated at the first alanine position.
	6. some alanines in newly synthesized proteins will be replaced with serine.

	1. by one of the aminoacyl tRNA sythetases.
	2. such that the amino acid is bound to the 5' end of the tRNA.
	3. None of these, the bond between tRNA and its amino acid is not covalent.
	3. None of these, the bond between tRNA and its amino acid is not covalent.
	5. once the correct tRNA has bound the codon in the A site of the ribosome.
	6. by a ribosomal subunit at the P site.

	1. Failure to terminate translation at stop codons.
	2. increase in the rate of transcription.
	3. decrease in the accuracy of translation.
	4. decrease in the rate of translation.
	5. Termination of translation before reaching a stop codon.
	6. increase in the rate of translation.
	7. decrease in the rate of transcription.