Actually, Julie does not use what you refer to as an "uno," but she uses a "woman's knife" that is specifically referred to as a "ulo." This ulo is one of the items Julie makes sure to take from her marital home when she leaves Daniel (her mentally ill husband) after he attempts to rape her. (Julie also takes warm clothes and some matches.)
Julie's ulo is an absolute necessity in that it can be used in numerous ways, most specifically as a hunting knife as well as a cooking knife. Although the use is often only implied, the reader sees Julie using her ulo many times in order to cut caribou meat to dry, to cut a hide from an animal, or even to cut small bits in order to feed her bird friend, a baby golden plover that Julie names "Tornait."
Julie also uses her ulo in order to memorialize the wolf, Amaroq, after he is killed. Previously, Julie shows her devotion to Amaroq by caving his beautiful wolf image into a piece of bone with her ulo. She keeps this memento with her at all times. It becomes increasingly important after Amaroq's death by hunters. Julie kneels over Amaroq's dead body and sings in her native Eskimo language. While holding the piece of bone with Amaroq's image carved into it, Julie turns this piece into a totem that carries Amaroq's spirit. Now Amraroq can be with Julie always.