Question

Roles of various phospholipids include all of the following except A. cell-cell recognition. B. a surfactant function in lung. C. activation of certain membrane enzymes. D. signal transduction. E. mediator of hypersensitivity and acute inflammatory reactions.

Short answer

A. Cell-cell recognition B. Surfactant function in lung C. Activation of certain membrane enzymes D. Signal transduction E. Mediator of hypersensitivity and acute inflammatory reactions Answer: E. Mediator of hypersensitivity and acute inflammatory reactions

Step-by-step solution

Understand Phospholipids Functions

Phospholipids are essential components of cell membranes. They play various important roles within cells, including: cell-cell recognition, surfactant function in the lung, activation of certain membrane enzymes, and signal transduction.

Analyze Given Options

We will now analyze each of the given options in relation to their roles as phospholipids: A. Cell-cell recognition: Phospholipids are an integral part of cell membranes, and certain membrane proteins are responsible for allowing cells to recognize and interact with each other, so this option is a correct role of phospholipids. B. Surfactant function in lung: Phospholipids, such as phosphatidylcholine, play a crucial role in lowering the surface tension of the alveoli in the lung as a surfactant, preventing lung collapse during exhalation. This option is also a correct role of phospholipids. C. Activation of certain membrane enzymes: Some membrane-bound enzymes require the presence of phospholipids for activation or interaction as a cofactor, so this is also a role of phospholipids. D. Signal transduction: Phospholipids also participate in signal transduction pathways, allowing cells to respond to external stimuli, such as hormones, and regulate cellular functions. This role is also correct for phospholipids. E. Mediator of hypersensitivity and acute inflammatory reactions: This function is associated with other biomolecules such as histamine and prostaglandins, which are released during inflammation and not directly related to phospholipids. Hence, this option is NOT a role of phospholipids.

Choose the Correct Answer

Since option E is the only one that is not a role of phospholipids, the correct answer is: E. mediator of hypersensitivity and acute inflammatory reactions.