Physiology Which of the following is not a major function of the endoplasmic reticulum (ER)? A Synthesis of lipids B Synthesis of proteins C Providing enzymes that control glycogen breakdown D Secretion of proteins synthesized in the cell 💡 Explanation Which of the following is not a major function of the endoplasmic reticulum (ER)? ✓ Correct Answer: D. Secretion of proteins synthesized in the cell