Question

which amino acid is specified by the codon aca?
second letter
first letter
third letter
write your answer as the three - letter amino acid abbreviation. write stop for a stop codon.

Explanation:

Locate the codon ACA by first finding the first letter 'A' in the left "First letter" column, then the second letter 'C' in the top "Second letter" row, and finally the third letter 'A' in the right "Third letter" column. The corresponding amino acid for this codon is threonine, whose three-letter abbreviation is Thr.

Answer:

Thr