[Campbell Biology P.396] What would be the most likely immediate effect on protein synthesis... | Practice Question

What would be the most likely immediate effect on protein synthesis if cells were treated with an agent that specifically removed the 5' cap from mRNAs?

  • A: Transcription of DNA into mRNA would cease.
  • B: The mRNA would be less stable and translation initiation would be impaired.
  • C: Introns would not be removed from the mRNA.
  • D: Amino acids would no longer be able to bind to tRNA molecules.

Explanation

The 5' cap plays crucial roles in protecting mRNA from degradation by exonucleases and in facilitating the binding of the ribosome to the mRNA to initiate translation. Without the 5' cap, the mRNA would be quickly degraded, and even if it persisted, the ribosome would have difficulty recognizing and binding to it, severely impairing protein synthesis.