The player character, it is implied that Chell was kept in suspended animation after GLaDOS took control of the Aperture Science facility. She wears an orange jumpsuit and protective knee springs to prevent damage from falling. Her name is not mentioned during the game, but is shown in the end credits when the actress (Alésia Glidewell) is thanked for providing the face model for Chell.
GLaDOS claims that in Chell's file it states that she is: "A bitter, unlikeable loner whose passing shall not be mourned" and that Chell is adopted. However, this information is doubtful since GLaDOS is, by her own admission, a liar.
Chell's fate at the conclusion of Portal is left ambiguous, as the player's last view from her perspective is of lying on the ground at the entrance to Aperture Laboratories. After a March 3, 2010 patch, however, the ending is slightly changed with a robotic voice approaching from behind and Chell being dragged away. Valve later confirmed that Chell is taken back into the lab and once again put in suspended animation.
Source: Wikipedia, "List of Half-Life universe characters", available under the CC-BY-SA License.