In prokaryotes, genes can exist as operons that are transcribed into a polycistronic mRNA, containing multiple genes in a single transcript. In eukaryotes, transcripts exist only as monocistronic mRNA containing a single gene. What fundamental genetic difference is responsible for this distinction?

Complete question:

Question: In prokaryotes, genes can exist as operons that are transcribed into a polycistronic mRNA, containing multiple genes in a single transcript. In eukaryotes, transcripts exist only as monocistronic mRNA containing a single gene. What fundamental genetic difference is responsible for this distinction?

(A) mRNA is transported outside of the nucleus in eukaryotes.

(B) Prokaryotic mRNA has a five-prime GTP cap.

(C) Prokaryotes use a single start codon for multiple genes.

(D) In eukaryotes, each gene has its own transcription initiation site

Answer:

(D) In eukaryotes, each gene has its own transcription initiation site

Explanation:

Eukaryotic mRNAs are monocistronic in nature which means that one mRNA carries the single transcript to be encoded. Each monocistronic mRNA is encoded by a stretch of a gene that has a specific initiation site to start the process of transcription. On the other hand, prokaryotes have some mRNAs that carry the code for two or more different polypeptides. These mRNAs are called polycistronic. For a polycistronic mRNA, multiple transcripts are transcribed under the single transcription initiation site.