Question

Statement I : The codon ‘AUG’ codes for methionine and phenylalanine. 
Statement II : ‘AAA’ and ‘AAG’ both codons code for the amino acid lysine. In the light of the above statements, 
choose the correct answer from the options given below

• A. Statement I is incorrect but Statement II is true
• B. Both Statement I and Statement II are true
• C. Both Statement I and Statement II are false
• D. Statement I is correct but Statement II is false

Answer 1

The Correct Option is A

To determine the correctness of the given statements about codons and amino acids, let's analyze each statement separately.

1. Statement I: The codon ‘AUG’ codes for methionine and phenylalanine.
   • The codon AUG is known as the start codon and it specifically codes for the amino acid methionine in eukaryotes. It does not code for phenylalanine. Instead, phenylalanine is coded by the codons UUU and UUC.
   • Therefore, Statement I is incorrect.
2. Statement II: ‘AAA’ and ‘AAG’ both codons code for the amino acid lysine.
   • The codons AAA and AAG indeed code for the amino acid lysine. This is accurate according to the genetic code.
   • Therefore, Statement II is true.

Based on the analysis above, we conclude:

• Statement I is incorrect but Statement II is true.

Hence, the correct option is: Statement I is incorrect but Statement II is true.