What are receptors predominantly made of in cell membranes?

Receptors in cell membranes are predominantly made of proteins. These proteins play a crucial role in cellular communication by binding to specific ligands, such as hormones or neurotransmitters, which activates a response within the cell. The structure of these receptor proteins allows them to interact specifically with their corresponding signaling molecules, initiating various intracellular processes.

Proteins are essential for this function because their diverse structures can form complex three-dimensional shapes necessary for binding with specific molecules. This specificity and the ability to undergo conformational changes upon ligand binding are fundamental to the signaling pathways they orchestrate, enabling cells to respond accurately to changes in their environment.

In contrast, while carbohydrates can be attached to proteins or lipids in the form of glycoproteins or glycolipids, they do not serve as the main framework for receptors. Nucleic acids, such as DNA or RNA, are involved in genetic information storage and transfer, but they do not play a direct role in membrane receptor structure. Lipids contribute to membrane structure and can form lipid rafts, but they do not serve the functional purpose of receptor signaling as proteins do.