What is the average required to get into biochem for second year?
especially for biomedical specialization

Hmm... probably about a 9-10 average.
I know Chem Bio you needed around 9.5-10 at least in your science and math courses, with things like chemistry weighted heavier than other stuff.
Your psych marks couldnt really matter less.
But this above is for entry into chem bio.

I believe the biomed specialization takes approximately 40 people, so it would be more competitive. A 10 should be fine, though.

This is what I found out from the Associate Dean's and the Chair of Biochem:

Biochem (Core and Specializations) Cutoff: 8.0 CA last year.