24. Defend Gamow’s hypothesis about the genetic code with some of its salient features.

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 24. Defend Gamow’s hypothesis about the genetic code with some of its salient features.

answers:

(i) George Gamow suggested that the genetic code should be made up of a combination of three nucleotides.
(ii) He proposed that if 20 amino acids are to be coded by 4 bases, then the code should be made up of three nucleotides. 4 = 64 (4 = 16), which is less than 20. So, the codon was proposed to be triplet.

Characteristics of the Genetic Code

The genetic code has a number of important characteristics.

  • The genetic code is universal. All known living organisms use the same genetic code. This shows that all organisms share a common evolutionary history.
  • The genetic code is unambiguous. Each codon codes for just one amino acid (or start or stop). What might happen if codons encoded more than one amino acid?
  • The genetic code is redundant. Most amino acids are encoded by more than one codon. In Figure above, how many codons code for the amino acid threonine? What might be an advantage of having more than one codon for the same amino acid?

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