Question

Phospholipids synthesis

• A. Happens solely in the smooth endoplasmic reticulum
• B. Begins in the rough endoplasmic reticulum and ends in Golgi apparatus
• C. Happens solely in Golgi apparatus
• D. Happens in Mitochondria

Hint:

Lipid Biosynthesis: Begins on the cytosolic leaflet of the ER membrane $\rightarrow$ Final modifications, glycosylation, and sorting occur in the Golgi Apparatus.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Glycerophospholipid and sphingolipid biogenesis is compartmentalized across the endoplasmic reticulum and Golgi network.

Step 2: Detailed Explanation:
In eukaryotic lipid cell biology:
1. Endoplasmic Reticulum (ER): The initial enzymatically catalyzed condensation steps of phospholipid synthesis (e.g., synthesis of phosphatidic acid, diacylglycerol, phosphatidylcholine, and phosphatidylethanolamine) occur on the cytosolic face of the endoplasmic reticulum (RER and SER).
2. Golgi Apparatus: Newly synthesized phospholipids and ceramide precursors are transported via vesicle budding or lipid-transfer proteins to the Golgi apparatus for terminal enzymatic modification, sphingomyelin synthesis, head-group glycosylation (glycolipids), and targeted sorting.

Step 3: Final Answer:
Thus, phospholipid synthesis begins in the endoplasmic reticulum and finishes in the Golgi apparatus, corresponding to option (B).