NEETZoologyMolecular Basis of Inheritance
Read the following statements regarding the salient features of the genetic code and choose the incorrect statement.
Options
- AThe rule that a specific codon codes for the same amino acid is universal and applies without any exceptions i
- BThe codon AUG has dual functions, as it codes for methionine and also acts as an initiator codon.
- COne codon codes for only one amino acid, hence the genetic code is unambiguous and specific.
- DThe codons UAA, UAG, and UGA do not code for any amino acids and function as stop codons.
Correct answer
A. The rule that a specific codon codes for the same amino acid is universal and applies without any exceptions i
Step-by-step solution
The genetic code is nearly universal. For example, from bacteria to human, UUU would code for phenylalanine. However, it is not without exceptions. NCERT explicitly states that some exceptions to this rule have been found in mitochondrial codons and in some protozoans. Thus, the statement claiming it applies without any exceptions is incorrect. AUG coding for methionine and acting as an initiator codon is a correct statement. The unambiguous and specific nature of the code means one codon codes for only one amino a