Question

question 6 (4 points) (03.03 mc) a part of an mrna molecule with the following sequence is being read by a ribosome: 5-ccc - acg - 3 (mrna). the charged transfer rna molecules shown in the figure below (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. which of the following dipeptides will be formed? a. proline - threonine b. glycine - cysteine c. alanine - alanine d. cysteine - alanine

Explanation:

Step1: Recall base - pairing rules

In translation, mRNA codons pair with tRNA anticodons. A - U and G - C are the base - pairing rules. The mRNA sequence is read 5' to 3' and tRNA anticodons are in 3' to 5' direction. Given mRNA sequence 5'-CCC - ACG - 3'.

Step2: Find the anticodons

The anticodon for CCC is GGG and for ACG is UGC. Looking at the table, the amino - acid corresponding to GGG is Glycine and to UGC is Cysteine. So the dipeptide formed is Glycine - Cysteine.

Answer:

b. Glycine - Cysteine