Do colleges take into account the difficulty of the school you transfer from?

Hi! I was wonderin if colleges really do take into account the difficulty/grading system of the schools that each student comes from. My friend and I are both transferring from different schools and we were thinking about that fact that at her school the average in the science classes (bell curve) is typically set at a 3.5 gpa, and how at my school it is typically a 2.4-2.7. If getting average is so different at different colleges, do they consider this at all when looking at our grades, or are we still held at the same standards? Just curious. Thanks!