Question

Codon of alanine
A) CUC, CUA, CUG
B) GGG, GGU, GGA
C) GUG, GUC, GUA
D) GCU, GCC, GCG

Answer 1

Hint:A codon is a trinucleotide sequence of DNA or RNA that codes for specific amino acids. The nucleotides for DNA are a, G, C, T, and that of RNA is a, G, C, U. These nucleotide sequences form 20 amino acids.

Complete Answer:
The genetic code is the set of rules used by living organisms to translate the triplet nucleotide into amino acid sequence. The genetic code is similar in all organisms and a set of64 triplet codons code of 20 amino acids.Translation takes place in ribosomes. In translation, the mRNA carries the information for the sequence to be transcribed using a tRNA molecule to carry the synthesised amino acid that reads 3 nucleotides at a time.
For example AUG stands for methionine which is the start codon. On the mRNA reads AUG, translation of amino acid starts. For alanine, mRNA codons are GCU, GCC, GCG, and GCA.
CUC, CUA, CUG codes for leucine.
GGG, GGU, GGA codes for glycine.

Thus the correct answer is (D). Codon of alanine is GCU, GCC, GCG, and GCA.

Note: The genetic code codes for specific amino acids. A single amino acid can be coded by two or three specific codons. The codons are universal. There are certain codons which are called nonsense codons like UAA, UGA, UAG which do not code for any amino acid. They terminate translation.