Kathlene S. G. Joo ’11, a sophomore in Eliot House, died suddenly yesterday morning. Friends said that she combined a love for athletics and academics during her time at Harvard.

Hoping to attend medical school, the Pittsburgh, Pa. native studied neurobiology at the College, working to complete the pre-med curriculum. Outside of lab and lectures, Joo stayed involved in the medical community as a member of the Harvard Cancer Society, serving as a regular volunteer at Massachusetts General Hospital.

But Joo’s other passion was rugby, the rough-and-tumble sport that her friends said she embraced.

Teammates spoke of Joo’s spirit on the rugby field.

“The one thing that I feel most summed her up is that she never backed down from a challenge—be it something huge like her torn ACL in rugby, or something as small as an arm wrestling match,” Radcliffe Rugby co-captain Morgan M. W. Jessee ’09 wrote in an e-mail.

“Joo met life head-on, and it’s what I admire most about her,” Jessee continued. “She was an amazing person, a great friend, and her passing has left a huge void in many lives.”

Known for her speed and agility, Joo—who teammates said went by her last name on the field—played the back position on the team. In that capacity, Joo handled offense, scoring “more than a few times,” according to Aubrey M. Chamberlain ’10, who played on the rugby team with Joo last year.

“She was definitely one of the more athletically advanced members,” Chamberlain said, adding that Joo “was a really dedicated member of the team—gregarious, hardworking, and just very admirable.”

Students familiar with Joo in rigorous science classes recalled her likability.

“We worked on problem sets together,” said Kiara A. Tulla ’11, also a neurobiology concentrator in Eliot. “She was a really sweet girl, easy to work with, and just very bright.”

Just hours after emergency medical personnel surrounded the front of Eliot House early yesterday morning between 2 and 3 a.m., barring students from entering the House, Master Lino Pertile informed Eliot residents of Joo’s death via e-mail.

Later that morning, at around 10:30 a.m., College Dean Evelynn M. Hammonds notified all undergraduates of Joo’s death in an e-mail statement.

Neither administrator’s e-mail disclosed the cause of death, but both emphasized the availability of counseling resources at University Health Services and the Bureau of Study Counsel for students coping with an undergraduate death—the fourth this year—while preparing for the upcoming exam period.

Eliot House hosted an informal gathering yesterday afternoon to commemorate Joo’s life and offer support to students who knew her.

More than 40 people sat in a room in the Masters’ residence at the gathering, some silently praying, some shedding tears, and others offering roses and other flowers in memory of Joo.

As of yesterday afternoon, funeral arrangements were still pending, and Joo’s family was en route to Cambridge, according to Hammonds’ e-mail.

—Staff writer Ahmed N. Mabruk can be reached at amabruk@fas.harvard.edu.

—Please feel free to post memories of Kathlene Joo below.

CORRECTION: An earlier version of this article referred to Kathlene Joo as a junior at one point in the story. In fact, she was a sophomore.