Who is Ellen Gulden from One True Thing and what is their importance?

Ellen Gulden is a twenty-four-year-old editor who had been working in New York until her mother fell ill with cancer and her father guilt-tripped her into moving home to care for her. Throughout her whole life, Ellen has had a distant relationship with her mother, thinking she was better than her mother because she went to college while her mother dedicated her life to becoming the perfect housewife. This whole relationship changes when Ellen moves back home and is forced to get to know her mother as a person, not a prototype, learning about her mother's desires, fears, and other complexities. Ellen becomes a home-maker-in-training, learning how to cook, decorate, and sew, and even that she enjoys it. Throughout the months Ellen spends with her mother, she realizes everything her mother gave up to give her a better life and is shamed at the way she treated her mother during her teenage years and into adulthood.