Final answer:
The statement that messenger RNA is usually polycistronic in eukaryotes is False. Most eukaryotic mRNAs are monocistronic, coding for a single polypeptide chain.
Step-by-step explanation:
The statement that messenger RNA is usually polycistronic in eukaryotes is False.
Polycistronic mRNA is a single mRNA molecule that encodes multiple polypeptides. While polycistronic mRNA is commonly produced during prokaryotic transcription, most eukaryotic mRNAs are monocistronic, meaning they code for a single polypeptide chain.
This means that each mRNA molecule codes for just one polypeptide chain. In contrast, prokaryotic mRNA is often polycistronic, allowing a single mRNA molecule to encode multiple polypeptides.
The newly transcribed eukaryotic mRNAs also undergo several processing steps which are absent in prokaryotic mRNAs, making them more stable and longer-lasting in the cell.
This monogenic nature of eukaryotic mRNA allows for more precise control over gene expression and regulation.