The Old Court part of the college was completed 1448 whilst the Great Gatehouse, with its polygonal turrets, dates from 1733. This is the main vehicular access point from Trumpington Street.
The 'student accommodation' pic is actually the library of Darwin College - I don't think any of it is student rooms. One of the nicer examples of 1970s (?) architecture in Cambridge, I think. Incidentally the old part of Darwin (just visible on the left) was owned by Charles Darwin's family.