Same amino acid is coded by multiple codons d/t following :
Ans. is 'a' i.e. Degeneracy There are 20 amino acids, to be coded by 61 codons, so every amino acid except methionine and tryptophan are represented by more than one codon. This is k/a degeneracy or redundancy.The genetic code is made up of codons. Codons consist of a sequence of three nucleotides i.e. it is a triplet code. Since there are 4 different nucleotides, their various combination leads to 64 codons (43). Three of these codons do not code for any specific amino acid (known as nonsense codons) and are used as termination signals (hence also known as termination or stop codons. When one of these termination codons appear in an mRNA sequence, it signals that polymerization of amino acids into a protein molecule is complete.Characteristics of the Genetic CodeSpecific or UnambiguousA given codon designates only one single specific amino acid.Degenerate or RedundantAlthough each codon corresponds to a single amino acid, a given amino acid may have more than one triplet coding for it.Exceptions are Methionine & Tryptophan, which have a single codon.Codons that represent same amino acids are called as synonymsIn general, the third nucleotide in a codon is less important than the first two in determining the specific amino acid. This is k/a third base degeneracy or wobbling phenomenon.UniversalIn all living organisms the genetic code is the same, this is k/a universality of the codeException is found in mitochondrial genome where AUA codes for methionine and UGA for tryptophan instead of isoleucine and termination respectively.Non-overlappingThere is no overlapping i.e. no base functions as a common member of two consecutive codons.CommalessThere is no punctuation between the codons. The codons are arranged as a continuous structure. The last nucleotide of the preceding codon is immediately followed by the first nucleotide of succeeding codon.
Degeneracy
Frame-shift mutation
Transcription
Mutation
Regulation of Gene Expression 