With Tyler Perry and Oprah Winfrey as executive producers, this drama about an obese, illiterate black teen in Harlem practically guarantees some emotional uplift. But when it arrives, eventually, its authority is unimpeachable, so deeply has director Lee Daniels (Monster’s Ball) immersed us in the depths of human ugliness. Played by newcomer Gabourey Sidibe, Claireece “Precious” Jones could hardly ask for a more ironic nickname: she’s raped by her father and verbally, physically, and sexually abused by her mother (Mo’nique), a welfare wastrel determined to keep her daughter locked into the same cycle of poverty that ruined her. A dim light appears at the end of the tunnel when Precious transfers to an alternative school and falls under the guidance of a generous teacher (Paula Patton) and an attentive counselor (Mariah Carey). The girl’s story is almost unbearably painful, and when Precious finally reclaims her dignity and self-worth, her accomplishment seems genuinely heroic.