Answer:
In the Biblical Age, Ancient Israel had Priests called Kohanim (literally Hebrew for "Priests") who oversaw the sacrifices in the Great Temple and passed this position to their children. The Kohanim still exist today as the descendants of those Priests and commonly have the last name of Cohen or some variant to indicate their ancestry.
Kohanim, however, do not retain a strong religious function in Modern Judaism. The preacher and Jewish scholar have merged into the "Rabbi" which means "Teacher". These Rabbis run synagogues, interpret Jewish law, and generally guide the religion's various movements.