- A Secreted out of cell
- B Targeted to lysosomes
- C Retained in the ER lumen
- D Sent to mitochondria
Correct answer: C. Retained in the ER lumen
Explanation: KDEL (Lys-Asp-Glu-Leu) is the ER retention signal. Proteins with KDEL are retrieved from the Golgi and retained in the ER.
Concept context
Cell theory, prokaryotic vs eukaryotic cells, organelles and their functions. Foundation of all biology.