What is happening at the structure labelled X?

A. Synthesis of proteins
B. Transport of proteins to the nucleus
C. Modification of proteins prior to export
D. Secretion of proteins through the plasma membrane

A

There were some comments about the quality of the electron micrograph. Although most candidates answered this question correctly, many believed X was pointing at the Golgi apparatus and others at the endoplasmic reticulum. The discrimination index was poor for this question, as many stronger candidates did not answer it correctly.