Question

Mention any 2 features of genetic codes.

Answer 1

Genetic codes:

1. The genetic code contains the sequence of nitrogen bases—A, C, G, U—in an mRNA chain.
2. These four bases make up the codon of the genetic code.
3. There are 20 common amino acids in proteins.
4. Features of genetic code are-
5. The genetic code is universal means that all living organisms use the same genetic code and this shows that all organisms share a common evolutionary history.
6. The genetic code is unambiguous. Each codon stands for (encodes) one amino acid unless it codes for a start or stops signal.
7. Har Gobind Khorana developed a method for synthesizing RNA molecules with defined sequences.
8. Start codon: The start codon is the initial set of codons in an mRNA transcript that is translated by a ribosome.
9. In eukaryotes, the most common start codon is AUG which codes for methionine.
10. The non-AUG start codons are rare in eukaryotes.
11. For instance, the Candida albicans (fungus) use CAG as a start codon.
12. Stop codon: The stop codon is a termination codon that signals to stop a protein translation process.
13. This codon disassociates the ribosomal subunits, and thus disrupts the amino acid chain.
14. UAG, UAA and UGA are the standard stop codons.