Multiple Choice
Which of the following is not a type of transport?
318
views
13. Intracellular Protein Transport
Protein Sorting
Multiple Choice
In eukaryotic cells, where must the SRP (signal recognition particle) receptor be located to ensure co-translational targeting of secretory proteins?
A
On the cytosolic face of the rough endoplasmic reticulum (ER) membrane
B
In the nucleus associated with nuclear pore complexes
C
In the lumen of the rough endoplasmic reticulum (ER)
D
On the inner mitochondrial membrane facing the matrix
Verified step by step guidance1
Understand the role of the Signal Recognition Particle (SRP) in co-translational targeting: SRP binds to the signal sequence of a nascent polypeptide as it emerges from the ribosome, pausing translation and directing the ribosome-polypeptide complex to the correct membrane.
Identify where the SRP receptor must be located: Since SRP directs the ribosome to the membrane where the protein will be translocated, the SRP receptor must be positioned on the cytosolic side of that membrane to interact with the SRP-ribosome complex.
Recall that secretory proteins are targeted to the rough endoplasmic reticulum (ER) during translation, so the SRP receptor should be on the cytosolic face of the rough ER membrane to receive the SRP-ribosome complex.
Eliminate other options by considering their locations and functions: the nucleus and nuclear pore complexes are involved in nucleocytoplasmic transport, the ER lumen is inside the ER and inaccessible to cytosolic SRP, and the inner mitochondrial membrane is unrelated to the secretory pathway.
Conclude that the SRP receptor must be located on the cytosolic face of the rough ER membrane to ensure proper co-translational targeting of secretory proteins.
Related Videos
Related Practice
