Question

Choose the correct answers from the alternatives given:
Which of the following is not true of a codon?
a. It extends from one end of a tRNA molecule
b. It never codes for more than one amino acid
c. It may code for the same amino acid as another codon does
d. It consists of three nucleotides

Answer 1

Hint: Codon is nothing but the sequence of nucleotide bases which are three in number and code for aminoacid. Based on the information present on the codon, translation usually takes place.

Complete answer:
Genetic code describes the relationship between the DNA sequence and the protein that encodes the DNA sequence. Generally in the case of DNA replication and all the reading takes place in the gene in the group of the three bases.

In general there are 64 codons present, among them all only 61 codons code for aminoacids, whereas the remaining 3 codons act as stop codons.

When three nucleotides present as a single stretch we call it codon. We all know that nucleotides are made up of purines and pyrimidines, which are Adenine, thymine, guanine and cytosine where among those any three are present as triplets and code for amino acids.

Sometimes they code for the same amino acids. Most of the amino acids usually specified by the codon, more than one time, tRNA helps in the conversion of codons into proteins. In order to transfer tRNA has anticodons, which can pair up with the codon bases.

Important things about codons: It is a triplet of nucleotide bases, Codons are usually reductant, several codons represent the single amino acid, but there is no ambiguity.

So from the above explanation except about tRNA remaining options are right first is wrong as the tRNA end carries the anticodons, but not the codons.
So the option A is correct answer.

Note: To know more about the functions of codon and genetic code, it’s important to have knowledge regarding nucleotides and at the same time one should know about the transcription, translation and structure of tRNA molecules.