Question

State salient features of genetic code.

Class XII
Molecular basis of inheritance

Answer 1

1It acts as Start signal codon- codon that initiate protein synthesis. Normally AUG codes for Methionine 2 Acts as Stop Signal Codon(terminating codon/ non sense codon)- gives signal to stop protein synthesis example- UAA, UAG, UGA 3 Genetic code is universal for ex- AUG codes for methionine from bacterium to elephant 4 It is written without any punctuation 5 Degeneracy- there are several such codons which code for single amino acids but 1 codon do not code for many amino acids 6 It is non ambiguous- Normally a single codon has specific information for specific amino acid 7 Colinearity- Genetic code is collinear i.e their exists colinearity between the sequence and arrangement of codons with the sequence and arrangement of amino acid(polypeptide chain)

Answer 2

The salient features of genetic code are as follows:
1. 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.
2. One codon codes for only one amino acid, hence, it is unambiguous and     specific.
3. Some amino acids are coded by more than one codon, hence the code is         degenerate.
4. The codon is read in mRNA in a contiguous fashion. There are no punctuations. 5. The code is nearly universal.
6. AUG has dual functions. It codes for Methionine (met) , and it also act as initiator    codon.