What is the function of transcription factors?

• A. Transcription factors degrade RNA after transcription.
• B. Transcription factors recognize specific DNA sequences to recruit or stabilize RNA polymerase and regulatory complexes, enabling precise transcription initiation.
• C. Transcription factors unwind DNA using helicase activity.
• D. Transcription factors are enzymes that synthesize RNA.

Answer: (B)

Transcription factors control gene expression by binding to specific DNA sequences and guiding the transcription machinery to start transcription at the right place and time. They recognize promoter or enhancer regions and help recruit or stabilize RNA polymerase and other regulatory proteins, forming the initiation complex that allows RNA synthesis to begin accurately. This coordinating role explains why they are essential for turning genes on or off in response to signals, rather than directly making RNA, degrading RNA, or unwinding DNA themselves.

The other ideas don’t fit because transcription factors aren’t enzymes that synthesize RNA like RNA polymerase, nor do they function as RNA-degrading agents. They also don’t act as helicases to unwind DNA; that unwinding is accomplished by helicases and the polymerase complex during transcription.