Final answer:
The characteristic shared by enzymes and carrier proteins that allows them to only interact with certain molecules is known as specificity. It ensures that enzymes bind only with compatible substrates and that carrier proteins transport specific ions or molecules across cell membranes.
Step-by-step explanation:
The characteristic shared by enzymes and carrier proteins, in which the proteins interact only with certain molecules, is known as specificity. Specificity is crucial for enzymes as it allows an enzyme's active sites to bind only with substrates that have a compatible shape and charge. In the context of carrier proteins, specificity allows these proteins to transport specific ions or molecules across cell membranes by changing shape after the binding occurs.
This specificity contributes to the selective transport function of the plasma membrane and is important in processes such as passive transport and active transport.
Carrier proteins are typically specific to a single substance or a family of closely related substances. This ensures that each type of carrier protein is dedicated to transporting its specific solute across the membrane, contributing to the cell's overall regulation and transport efficiency. Examples include the GLUT1 transporter, which allows glucose to cross cell membranes but not other sugars like fructose or ribose. Overall, specificity is a defining characteristic of both enzymes and carrier proteins, allowing them to play their essential roles in biological systems.