Not sure about other schools, but it's possible to substitute Biochem for a portion of your chemistry requirement at UTSA. What's strange is that biochemistry is also a pre-req ... so I guess double-dipping for pre-reqs is allowed. I would check to make sure. The Ochem II requirement is standard requirement for basically every U.S. medical school.
http://som.uthscsa.edu/Admissions/prerequisites.asp
BIOCHEMISTRY: Three semester hours or 5 quarter hours of Biochemistry is required. This requirement may be used towards fulfilling the Biological Science or Chemistry requirement. The course may be taught in the Biology, Biochemistry or Chemistry department and cannot be an introductory course.