The codons for the various amino acids are given below. Answer the question.
Identify the sequence of amino acids in an mRNA AUG UUU UUA CCU UCG A___.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Met Phe Leu Pro Ser
Reading the codons from the table: AUG = Met, UUU = Phe, UUA = Leu, CCU = Pro, UCG = Ser.
Option (1) Met Phe Leu Ser Pro — Incorrect. Ser and Pro are in the wrong order; CCU (Pro) comes before UCG (Ser).
Option (2) Met Phe Leu Pro Ser — Correct. Reading the codons in order: AUG = Met, UUU = Phe, UUA = Leu, CCU = Pro, UCG = Ser. So the sequence is Met Phe Leu Pro Ser.
Option (3) Met Leu Phe Pro Ser — Incorrect. UUU is Phe and UUA is Leu, not the other way round.
Option (4) Phe Pro Leu Met Ser — Incorrect. The chain must begin with Met, coded by AUG.