Question

The Signal Recognition Particle (SRP):

Prevents proteins from being translocated into the ER

Guides bad proteins the proteasome (garbage disposal) for degradation

None of the above

Guides proteins bound for the ER to receptors in the ER membrane

Is not involved in protein trafficking

Answer 1

The Signal Recognition Particle (SRP): Guides proteins bound for the ER to receptors in the ER membrane

Signal recognition particle (SRP) recognizes the polypeptide and binds to the signal sequence of newly synthesized polypeptide as it emerges from the ribosomes. It then targets the protein-ribosome complex through the protein conducting channel or translocon in the endoplasmic reticulum membrane. Thus, SRP is responsible for guiding proteins bound for the ER to receptors in the ER membrane.