Question

Lecithin is the common name of:

• A. Phosphatidyl ethanolamine
• B. Phosphatidyl choline
• C. Phosphatidyl Serine
• D. Phosphatidyl Inositol

Hint:

Lecithin is widely used in the food industry as an emulsifier (e.g., in chocolate, mayonnaise, and margarine) to prevent water and fat phases from separating.
Egg yolk and soybeans are rich natural sources of lecithin.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Phospholipids are a major class of lipids that serve as structural components of cell membranes.
They are composed of a glycerol backbone, two fatty acid chains, a phosphate group, and a nitrogenous base or polar head group.
Many common phospholipids are referred to by traditional or commercial names.

Step 2: Detailed Explanation:
Lecithin is the widely accepted common name for phosphatidylcholine.
- Chemically, it consists of a glycerol molecule esterified with two fatty acids at the \( \text{sn}-1 \) and \( \text{sn}-2 \) positions.
- The third hydroxyl group (\( \text{sn}-3 \)) is linked to a phosphate group, which in turn is attached to a choline molecule (a quaternary ammonium cation).
- It is an amphiphilic molecule containing both a hydrophobic tail (fatty acids) and a hydrophilic head (phosphorylcholine), making it an excellent natural surfactant and emulsifier.
Other phospholipids have different common names or structures:
- Phosphatidyl ethanolamine is commonly known as cephalin.
- Phosphatidyl serine and phosphatidyl inositol are also key membrane lipids but are not referred to as lecithin.
Therefore, lecithin is the common name of phosphatidylcholine.

Step 3: Final Answer:
Lecithin is the common name of Phosphatidyl choline.