Question

drag and drop the following events into the correct order to show how proteins enter the endoplasmic reticulum. place the first event at the top and the last event at the bottom. mrna is exported from nucleus and associates with ribosomes in the cytoplasm protein is inserted into the interior (lumen) of the endoplasmic reticulum signal sequence of new protein binds to rna - protein complex rna - protein complex guides ribosome complex to the endoplasmic reticulum membrane signal sequence is removed

Explanation:

Protein - targeting to the endoplasmic reticulum (ER) starts with mRNA export from the nucleus and ribosome - association. Then the signal sequence of the new protein binds to the RNA - protein complex. This complex guides the ribosome complex to the ER membrane. After that, the protein is inserted into the ER lumen and finally, the signal sequence is removed.

Answer:

1. mRNA is exported from nucleus and associates with ribosomes in the cytoplasm
2. signal sequence of new protein binds to RNA - protein complex
3. RNA - protein complex guides ribosome complex to the endoplasmic reticulum membrane
4. protein is inserted into the interior (lumen) of the endoplasmic reticulum
5. signal sequence is removed