Question

Which of the classes of RNA molecules is found in almost no prokaryotes?

Options

• Ribosomal RNA

• Transfer RNA

• Messenger RNA

• Primary mRNA transcript

Answer 1

Primary mRNA transcript

Explanation:

In prokaryotes, there is no nucleus, so transcription and translation happen at the same time. As soon as the RNA is made, ribosomes start building proteins from it immediately. Because of this “real-time” process, there is no need for a primary mRNA transcript (pre-mRNA) to sit around and wait for processing. In eukaryotes, however, the primary transcript must be edited and “spliced” inside the nucleus before it can be used.