Galactose permease is a protein found in the cell membranes of certain organisms, including yeast. Its primary function is to facilitate the transport of galactose, a type of sugar, into the cell. This process is essential for cells that utilize galactose as an energy source, especially when other sugars are not available. The protein operates through a mechanism known as facilitated diffusion, allowing galactose to move across the membrane without the expenditure of energy. Galactose permease is encoded by the GAL2 gene in yeast, highlighting its importance in cellular metabolism and energy production.