Final answer:
True, a 30S ribosomal subunit is prevented from interacting with initiation factors when it is about to join with the 50S subunit, a process inhibited by IF3 during the initiation of protein synthesis.
Step-by-step explanation:
The statement is true; a 30S ribosomal subunit cannot interact with initiation factors (IFs) when it is going to associate with a 50S subunit during the initiation of protein synthesis. This interaction is specifically prevented by IF3, which binds to the 30S subunit, thereby interfering with the formation of the initiation complex between the 50S and 30S subunits. It is only after the initiation complex is formed, which includes the mRNA and initiator tRNA, that the 30S subunit can then associate with the 50S subunit to begin translation.