Question

Retinoic acid (a derivative of vitamin A; Section 9-1 F) is a hormone that mediates immune system function. Would retinoic acid require a receptor on the surface of a target cell?

Short answer

Retinoic acid does not require a receptor on the target cells’ surface.

Step-by-step solution

Concept Introduction

The body need modest amounts of Vitamin A to function and stay healthy. Vitamin A is used to make retinoic acid, which aids cell growth and development, particularly in the embryo.

Requirement of a Receptor

A hormone must be lipid-soluble to reach the cytoplasm of a target cell and pass through the cell membrane. Because retinoic acid is lipid-soluble, it does not require a receptor on the cell surface to function as it can easily penetrate through the cell membrane.

Therefore, no cell-surface receptor is required for retinoic acid.