Question

Wild-type strains of E. coli have a tRNA with a 5′-GUA-3′ anticodon that recognizes the UAC codon for tyrosine. We can represent this tRNA as GUA-tRNATyr. Suppose you isolated a strain of E. coli in which a mutation changed the anticodon in this tRNA to 5′-CUA-3′ (creating CUA-tRNATyr). Answer the following questions about translation elongation in each strain. For each answer, type in "yes" or "no".
A. Will the wildtype tRNA recognize a normal UAC codon in the A site?
B. Will the mutant tRNA recognize a normal UAC codon in the A site?
C. Will the wildtype tRNA recognize a stop codon in the A site?
D. Will the mutant tRNA recognize a stop codon in the A site?
E. Will peptide bond formation occur with the wildtype tRNA bound in the A site?
F. Will peptide bond formation occur with the mutant tRNA bound in the A site?
G. Will the normal, wildtype protein be produced in the wildtype strain?
H. Will the normal, wildtype protein be produced in the mutant strain?

Answer 1

Answer:

The anticodon of the mutant tRNA that is CUA will recognize UAG which is a termination codon or nonsense codon or stop codon.

Explanation:

A   yes

B   no

C  no

D  yes

E   yes

F  no

G   yes

H    no

In the mutant strain the tRNA recognizes a stop codon UAG  for this reason protein synthesis will terminate at the stop codon.