I'm in first year life sci and im wondering if the textbooks for chemistry 1a03, kin 1y03 and physics 1b03 crosses over and can be used for second semester, for chem 1aa3, kin 1yy3 and physics 1bb3. Or do we have to buy new textbooks again :(?

I can answer for Chem and Physics, yes, the book carries over. And for the physics one it damn well better, that book is pricey T.T

No, you do not need to buy two separate textbooks for each course. As stated above, chemistry and physics carry over. As well, the same textbook is used for both Kin 1Y03 and Kin 1YY3.