Question

The following information should be used for the questions.

A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3' (mRNA). The following charged transfer RNA molecules (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form.

The anticodon loop of the first tRNA that will complement this mRNA is
A. 3' UGC 5'
B. 5' GGC 3'
C. 5' ACG 3'
D. 5' UGC 3'
E. 3' GGC 5'

Answer 1

The correct anticodon loop for the first tRNA that matches the mRNA sequence 5' CCG-ACG 3' is option E, which is 3' GGC 5'. This matches the codon CCG for proline in the translation process.

Step-by-step explanation:

The sequence 5' CCG-ACG 3' on the mRNA strand corresponds to the codons for proline (CCG) and threonine (ACG). To assess which tRNA anticodon will be the first to complement this mRNA during the translation process, we need to remember that anticodons are antiparallel and complementary to codons. Therefore, for the codon CCG, the anticodon should read 3' GG-C 5', and for ACG, it should be 3' UG-C 5'. The correct anticodon loop of the first tRNA that will complement this mRNA is 3' GGC 5', which is option E, to pair with the codon CCG for proline.