Question

Termination codon is
A. UAA
B. UCG
C. AUG
D. UUU

Answer 1

Hint: The codon which is also known as nonsense codon or stop codon.It is named as ochre and responsible for termination of the translation ( protein synthesis)process. It doesn't code for any amino acid.

Complete answer:
A codon is a trinucleotide sequence of DNA or RNA that corresponds to a specific amino acid and is helpful in the process of protein synthesis. Termination codons are 3 in number that do not code for any amino acid. These 3 codons are UAA( ochre), UAG(amber) and UGA(opal). These codons are also known as stop codons because they terminate the translation process.

Additional information: A codon is formed by the combination of bases and by the help of permutation combination of these 4 bases, 64 codon are generated which code for 20 amino acids. This bold proposition was given by George Gamow. Out of these 64 codons, 61 code for amino acid while 3 codons do not code for any amino acids.

Hence the correct answer is option ‘A’.

Note: The codon is unambiguous and specific. One codon code for only one amino acid.
Sometimes one amino acid is coded by more than one codon hence the code is degenerate, example: -UCU,UCC,UCA and UCG all these 4 codon codes for a single amino acid that is serine. The codon is read in mRNA in a contiguous manner without any punctuation. The codon is nearly universal and code for the same amino acid in all living organisms from bacteria to humans.