Tsukino Ikuko is Usagi's mother in the anime and manga Bishoujo Senshi Sailor Moon. If you've only watched the dub, or don't pay attention to names for some reason, she's the purple haired lady. ^^;;
Ikuko's main role before the arrival of Chibi-usa is pretty much to hound Usagi about her grades. The first time we really get to see her in action is the first episode. She's run into Umino who's blabbed about their test that Usagi did HORRIBLY on. When Ikuko see's the low mark she flips out and kicks Usagi out of the house telling her to study, she's a disgrace to the family. She also works to keep the Tsukino house nice and neat [with Shingo's help] because let's face it, Usagi's housekeeping skills leave much to be desired. Ikuko also cooks and keeps Usagi and her family well fed [hey, you never see them complaining, do you?]

What's she like?
  Ikuko is a lot like Usagi at times. Very excitable, very odd hair, very bad at math.... but she's a mature Usagi I guess. She's very smart, and very wise, especially in the way of how to treat her daughter. She teases Usagi and can be hard on her, but it's obvious that the two love each other. Ikuko is the glue of the Tsukino family, you could say. She makes sure her husband, Kenji, is doing his job and keeps him informed of what's going on, she keeps an eye out for Shingo and Usagi and attempts to keep their sibling squabbling to a minimum. Ikuko is your everyday mommy. Not perfect, but a wonderful mom nonetheless. ^^