Question

Which of the following is true of RNA synthesis (transcription)?

• A. RNA synthesis is always in the 5' - 3' direction
• B. RNA polymerase needs a primer to initiate transcription
• C. In transcription, U is inserted opposite T
• D. New nucleotides are added on to the 2' OH of the ribose sugar

Answer 1

The correct option is A RNA synthesis is always in the 5' - 3' direction

In transcription, as in DNA replication, nucleotides are added on to the 3' OH of the growing chain so RNA synthesis is always in the 5' - 3' direction. Unlike DNA synthesis, a primer is not needed for initiating a new strand. RNA contains U instead of T, and U base pairs with A and is inserted opposite A (not T) in the template.