What family of molecules is crucial for cell-to-cell recognition?

Membrane receptors play a pivotal role in cell-to-cell recognition because they are proteins located on the cell surface that interact with specific molecules, such as ligands, to transmit signals across the cell membrane. This interaction initiates a physiological response essential for various cellular processes, including communication between cells, immune response, and tissue repair.

These receptors can recognize specific carbohydrates, proteins, and other molecules on neighboring cells, which is crucial for processes like tissue formation and immune system function. For example, in the immune system, membrane receptors help identify pathogens and activate immune responses.

The other options—neurotransmitters, enzymes, and hormones—serve different primary functions. Neurotransmitters facilitate communication between nerve cells, enzymes catalyze biochemical reactions, and hormones act as signaling molecules affecting various physiological functions in the body. Although all of these molecules are important for cell function and communication in some context, membrane receptors are specifically integral to the process of cell-to-cell recognition.