Determining the biochemical nature of genetic material and the structure of DNA was very exciting, the proposition and deciphering of genetic code were most challenging. In a very true sense, it required involvement of scientists from several disciplines – physicists, organic chemists, biochemists and geneticists.t was George Gamow, a physicist, who argued that since there are only 4 bases and if they have to code for 20 amino acids, the code should constitute a combination of bases. He suggested that in order to code for all the 20 amino acids, the code should be made up of three nucleotides. This was a very bold proposition, because a permutation combination of 43 (4 × 4 × 4) would generate 64 codons; generating many more codons than required.he 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. Some amino acids are coded by more than one codon, hence the code is degenerate. The codon is read in mRNA in a contiguous fashion. There are no punctuations.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. AUG has dual functions. It codes for Methionine (met) , and it also act as initiator codon. UAA, UAG, UGA are stop terminator codons.

The genetic code is degenerate, why?

It lacks specificity and one amino acid has more than one code triplet.

The correct answer is Option (4) - It lacks specificity and one amino acid has more than one code triplet.

Option 1: Universality is a separate concept. The genetic code is indeed universal, meaning most organisms use the same code, but it can still be degenerate within that universality.

Option 2: This statement isn't entirely accurate. There are very few "stop codons" that don't code for amino acids, but degeneracy refers to multiple codons for a single amino acid, not the absence of some codons.

Option 3: While the initiation codon (AUG) is unique, degeneracy refers to the redundancy within the remaining codons.

 So, the 4th option captures the essence of degeneracy: multiple codons specifying the same amino acid. This redundancy provides a buffer against mutations and helps with efficient protein synthesis.

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.