Which of the following molecules would coded for by the longest piece of DNA, assuming that no post-transcriptional RNA processing or splicing has occurred?

(A) : A protein with 25 amino acids

(B) : A polysaccharide with 60 sugars

(C) : A mRNA molecule with 20 codons

(D) : An mRNA molecule with 45 nucleotides

Answer: (A) : A protein with 25 amino acids

Explanation: Nucleotides are macromolecules composed ofa 5-carbon sugar (ribose), a nitrogenous base, and a phosphate group and represent the building blocks of both our DNA and RNA.

Both codons and amino acids are built out of 3 nucleotides. Thus, 25 amino acids will yield 75 nucleotides whereas 20 codons only 60. In conclusion, the protein is coded from the longest piece of DNA.

B has nothing to do with DNA or RNA coding.

A protein with 25 amino acids coded for by the longest piece of DNA, assuming that no post-transcriptional RNA processing or splicing has occurred.

The correct option is Option A i. e. A protein with 25 amino acids.

Explanation:

A codon is a "group of three nucleotides" on mRNA which codes a "particular amino acid" during the protein translation. Whereas nucleotide is a group of a pentose sugar, a nitrogen base, and a phosphate moiety.

A RNA molecule with 20 codons have 20*3=60 nucleotides. A protein with 25 amino acids will be coded by 25*3=75 nucleotides. So option A is correct. Option B i. e. Polysaccharide has no relation with nucleotides.