carrier molecule

1. A molecule that plays a role in moving electrons through the electron transport chain. They are usually proteins bound to non-protein groups and able to undergo oxidation and reduction relatively easily, thus allowing electrons to flow. 2. A lipid-soluble molecule that can bind to lipid-insoluble molecules and transport them across membranes. Carrier molecules have specific sites that interact with the molecules they transport. The efficiency of carrier molecules may be modified by changing the interacting sites through genetic engineering.