Question

Explain the Following: Degenerate code, Unambiguous code, Universal code, Initiator code.

Answer 1

Hint: Genetic code is a sequence of nucleotide bases. It consists of 3 bases which code for specific amino acids. For example AUG codes for Methionine. The translation starts from the start codon till it reaches the stop codon.

Complete Answer:
To solve this question, we must know about the characteristics of genetic code.
The genetic code is triplet. There are 64 codes made out of 4 bases which codes for specific amino acids.

The characteristics of genetic code are:
1. Degenerate code- The four nitrogenous bases form different combinations which code for 20 amino acids. More than one code can code for a single amino acid. This shows that the genetic code is redundant.

2. Unambiguous code- All the living organisms have the same code for coding amino acids. It means that a single codon can only code for only one amino acid.

3. Universal code-The universal nature of code states that a single code codes for the same amino acid irrespective of the organism. AUG codes for methionine in humans and also in dogs. This universal nature of code shows certain deviations but still it holds good in nearly all individuals.

4. Initiator code- Initiator code is also known as start codon. The start codon is AUG. The initiation of polypeptide chain synthesis starts with methionine.

Note: The polypeptide chain continues till it reaches the stop codons. Once the stop codons are achieved, the polypeptide synthesis terminates. The stop codons are UAA, UAG and UGA. They are also known as nonsense codons.