Identify the statements which are not true for the genetic code.

(A) 64 codons code for amino acids.
(B) The genetic code is nearly universal with some exceptions found in mitochondrial codons and some protozoans.
(C) Some amino acids are coded by more than one codon.
(D) AUC codes for methionine

Choose the correct answer from the options given below:

(A) and (D) only

The correct answer is Option (2) → (A) and (D) only

The salient features of genetic code are as follows:

(i) The codon is triplet. 61 codons code for amino acids and 3 codons do not code for any amino acids, hence they function as stop codons.

(ii) Some amino acids are coded by more than one codon, hence the code is degenerate. It lacks specificity and one amino acid has more than one code triplet that's why code is degenerate.

(iii) The codon is read in mRNA in a contiguous fashion. There are no punctuations.

(iv) The code is nearly universal: for example, from bacteria to human UUU would code for Phenylalanine (phe). Some exceptions to this rule have been found in mitochondrial codons, and in some protozoans.

(v) AUG has dual functions. It codes for Methionine (met) , and it also act as initiator codon.

(vi) UAA, UAG, UGA are stop terminator codons.