[Byrne]

Why is it that the anode is the negative electrode in a galvanic cell, but the positive electrode in an electrolytic cell?

[mike]

In the galvanic cell the anode (where oxidation is occurring) is the source of electrons for the cell and is thus the negative electrode.

In the electrolytic cell the anode (still where oxidation is occuring) is where the negative charge (anions in solution) are returning to the electrode (to complete the circuit) thus making it the positive electrode. While the cathode is getting electrons "pumped" into it from the external power source thus making it negative.