The document discusses the genetic code and the wobble hypothesis. It notes that the genetic code uses triplets of bases to code for amino acids, with 61 codons specifying amino acids and 3 being stop codons. It explains that the wobble hypothesis proposes that the third base of the codon pairs non-specifically with the anticodon through wobble pairing, allowing multiple codons to code for the same amino acid. This wobble pairing allows inosine, the fifth base found in tRNAs, to pair with multiple bases and increases the efficiency of translation.

1. Genetic Code and its Co-relation with
Wobble - Hypothesis

2. Genetic Code
● Consists of a “TRIPLET “, i.e. A sequence of 3 bases codes for a
particular amino acid .
●
There are 4³ or 64 possible combinations .
● Group of 3 bases coding for an amino acid in mRNA is called a
codon
PROPERTIES :
● Degenerate : An amino acid can be coded for by more than
one codon. Anti codon shows Wobble .
● Unambiguous : Each codon indicates a single , specific
amino acid .
● Non-overlapping : When translated , the reading frame is
advanced 3 bases at a time .

3. Genetic Code

4. Contd. .
● The base sequence is read from a fixed point , without any
punctuations.
● Out of 64 codons , 61 codons specify amino acid , while remaining 3
are nonsense or stop codons.
● The code is degenerate - except for Trp and Met,each amino acid is
coded by two or more codons .
● Codons are recognized by aminoacyl-tRNAs.
● Aminoacyl-tRNAs activate the amino acid for transfer to peptide
● Aminoacyl-tRNA synthetases does the critical job : linking the right
amino acid with "cognate" tRNA
● Reaction:
amino acid + ATP → aminoacyl-AMP + Ppi
aminoacyl-AMP + tRNA → aminoacyl-tRNA + AMP
Sum of 1 and 2:
amino acid + tRNA + ATP → aminoacyl-tRNA + AMP + PPi

5. Wobble in the anti codon :
● In 1966, Francis Crick ,proposed “the Wobble
hypothesis”.According to this hypothesis, only the first two
bases of the codon have a precise pairing with the bases of the
anticodon of mRNA, while the pairing between the third bases
of codon and anticodon may Wobble (non specific).
● The pairing between the first two bases is normal, while
between G and U is against the normal pairing pattern. This
unusual bonding between G and U is called Wobble pairing.
● Inosine is the fifth base in the anti codon.
● Inosine arises through enzymatic modification of adenine by
ADAR-Adenosine Deanimase RNA specific .
● Inosine is commonly found in tRNAs and is essential for proper
translation of the genetic code in wobble base pairs.
● Advantage of wobble: dissociation of tRNA from mRNA is faster