Question

Which of the following is true about glycerophospholipids? (A) \(\quad\) Glycerophospholipids can sometimes be sphingolipids, depending on the bonds in their head groups. (B) \(\quad\) Glycerophospholipids are merely a subset of phospholipids. (C) \(\quad\) Glycerophospholipids are used in the \(A B O\) blood typing system. (D) \(\quad\) Glycerophospholipids have one glycerol, one polar head group, and one fatty acid tail.

Short answer

B is true because glycerophospholipids are a subset of phospholipids.

Step-by-step solution

Understand Glycerophospholipids

Glycerophospholipids are a type of phospholipids that contain a glycerol backbone, two fatty acid tails, and a phosphate group which is typically linked to another organic molecule.

Evaluate Option (A)

Glycerophospholipids and sphingolipids are distinct classes of lipids. Sphingolipids have a sphingosine backbone, not a glycerol backbone. Hence, glycerophospholipids cannot be sphingolipids depending on their bonds.

Evaluate Option (B)

Glycerophospholipids are indeed a subset of phospholipids, as phospholipids can be based on either glycerol (as in glycerophospholipids) or sphingosine (as in sphingolipids).

Evaluate Option (C)

The ABO blood typing system involves glycosphingolipids, not glycerophospholipids. Thus, glycerophospholipids are not used in the ABO blood typing system.

Evaluate Option (D)

Glycerophospholipids consist of one glycerol, two fatty acid tails, and one phosphate group which is usually linked to a polar head group. They do not have just one fatty acid tail.

Key concepts

Phospholipids

Phospholipids are a major class of lipids essential for building cell membranes. Unlike simple fats, phospholipids have a key structure which includes two fatty acid tails and a phosphate group attached to a glycerol backbone. This unique structure allows them to form the bilayer of cell membranes, with hydrophilic (water-loving) heads facing outward and hydrophobic (water-fearing) tails facing inward. This dual nature is crucial in maintaining the integrity and function of cellular membranes.

Lipid Structure

Lipids are a diverse group of molecules, but their common feature is being hydrophobic (water-insoluble). This includes fats, oils, and certain types of vitamins. The fundamental structure of many lipids includes long hydrocarbon chains that make them non-polar. Phospholipids, a type of lipid, have a unique structure because of their amphipathic nature, meaning they contain both hydrophobic and hydrophilic parts. This structural feature is essential for forming cellular membranes and facilitating various biological processes.

ABO Blood Typing System

The ABO blood typing system is a method of classifying human blood based on the presence of certain antigens on the surface of red blood cells. These antigens are glycolipids, specifically glycosphingolipids, not glycerophospholipids. The different blood types (A, B, AB, and O) are determined by variations in the carbohydrate chains present on these glycosphingolipids. Understanding this system is critical in clinical settings, especially for blood transfusions and organ transplants to ensure compatibility.

Glycerol Backbone

The glycerol backbone is a simple three-carbon molecule that serves as the foundation for various types of lipids, including triglycerides and phospholipids. In glycerophospholipids, the glycerol backbone is linked to two fatty acid chains and one phosphate group. The phosphate group, in turn, can be bonded to different types of head groups, often forming a polar (hydrophilic) region. This structure allows glycerophospholipids to play a crucial role in forming the lipid bilayer of cell membranes, providing stability and fluidity.