Question

In prokaryotes, how does the length of a typical monocistronic mRNA compare to the length of the protein generated from this mRNA? a. There are more mRNA bases than amino acids. b. There are more amino acids than mRNA bases. c. The number of amino acids and the number of mRNA bases are roughly the same.Which of the following statements support the previous conclusion that there are more mRNA bases than amino acids? NOTE: While there may be some rare exceptions that don't support the conclusion, choose statements that typically support the conclusion Select all that apply. a. The mRNA contains a poly-A tail. b. The stop codon does not code for an amino acid. c. The start site of transcription is upstream of the start codon. d. The mRNA contains 5' and 3 untranslated regions. e. O Introns have been removed in the mRNA. f. Each codon contains 3 RNA bases. g. The mRNA contains a 7-methylguanosine cap.

Answer 1

1. The correct answer is: a. There are more mRNA bases than amino acids.

The transcription of monocistronic mRNA in prokaryotes is a rare process (it is more characteristic for the eukaryotes). Monocistronic mRNA is RNA, which encodes for only one or specific protein. Three bases of mRNA encode one amino acid of protein, thus it has more bases than amino acids of the final product, protein.  

2. The correct statements are:  

The mRNA contains 5' and 3' untranslated regions.

The stop codon does not code for an amino acid.

The start site of transcription is upstream of the start codon.

Each codon contains 3 RNA bases.

All of these approve that more bases are in mRNA since not all of them are translated into amin oacids.

Other statements are hallmarks of eukaryotic RNA processing, and therefore not relevant to prokaryotes.