The invention relates to a polypeptide featuring a novel specific arabinose transporter function as well as nucleic acids coding therefor. The invention further relates to host cells, particularly modified yeast strains which contain the coding nucleic acids and express the polypeptide and functionally integrate the same into the plasma membrane, thus being able to absorb L-arabinose. When using modified host cells expressing additional proteins of the arabinose metabolic pathway, arabinose can be fermented, especially into ethanol, by means of said cells. The invention is thus significant, among other things, in connection with the production of biochemicals from biomass, e.g. bioethanol.