A reality show will rise or fall on two things: concept and casting.

"America's Next Top Model," which wraps up its first season on UPN this week, had a proven concept to begin with -- it's an "American Idol"-style competition in which aspiring models compete for a contract, with one of the 10 finalists being sent home each week.

The show scored with its casting as well, thanks in part to 20-year-old Elyse Sewell. A self-described "nerdy scholar" from Albuquerque, N.M., Sewell is one of three remaining finalists -- along with Chicagoan Adrianne Curry and Ohio native Shannon Stewart -- for the top prize of a management contract, a deal with Revlon and a guaranteed appearance in the pages of Marie Claire magazine.

The finale airs at 9 p.m. ET Tuesday (July 8) on UPN, preceded by an hour of highlights from the series at 8 p.m.

Although she now has a 33-percent chance of winning, Sewell was ready to pack it in during the early days of shooting the show. She attributes her early difficulties, including a bleep-filled tirade against several fellow contestants, to being "out of my element" in New York and in the finalists' cramped quarters.

"I tried to go into it with an open mind, but I quickly grew really tired and impatient and frustrated and full of rage," she says. Of her now-infamous rant, Sewell says it was brought on by some things that didn't air, "but there's also no excuse for that tirade, except for me temporarily becoming a basket case. I sort of lost it."

As the show played out, though, Sewell warmed to the competition and became one of the favorites. She has received mostly positive feedback from host/executive producer Tyra Banks and the other fashion-industry pros who judge the competition -- not bad for someone whose previous modeling experience consisted of a fashion show at a local mall.

Sewell says she's learned a lot about being a model, although the job is not as tough as, say, research in biochemistry, which she did as a student at the University of New Mexico. (She graduated in three years with degrees in biology and Spanish.)

"It's easier," she says. "Better clothes, more standing around, better food."

That's not to say that standing on a New York rooftop in a swimsuit in January -- as the finalists did in an early photo shoot -- was all giggles.

"You may have noticed in the show [that] the word 'extreme' precedes a lot of the tasks we do," Sewell says. "So I think the show was a little extreme. ... The photographer [at the rooftop shoot] said he'd never had a girl in a situation like that before."

Nor was the very real rift between Sewell and Curry -- whom Sewell jokingly refers to as "the hell-bound" -- and several contestants with strict Christian beliefs, most notably Robin Manning, who was eliminated in last week's episode.

The split came to a head in the last episode, in which Sewell first tried to strike a compromise between Manning and Stewart, who wanted to spend an off day shopping, and Curry, who wanted to see Jim Morrison's grave.

"That for me was the turning point between trying to be diplomatic between the hell-bound and the Christians," Sewell says, "and just absolutely openly despising Robin for the rest of the time she was there. At that point I completely gave up on good relations between myself and Robin."

Sewell worked as a teaching assistant after graduating, and she still plans to go to medical school. She won't reject what comes her way if she wins the "Top Model" crown, however; in fact, it could pay her med-school tuition.

"If I were to win, I would milk it for all it's worth," she says. "It would be nice to get some money, be nice to do the work, it'd be great to do the travel. I'd love to win."