This will involve a little bit of research yourself, im afraid!
You have to look at all the Unis you are interested in and all the courses on their websites and see what the entry requirements are. Heres a few things to look out for:
1. What points/grades they look for - some unis ask for a certain number of points and some ask for grades for example, 280 points, or ABB. Some criteria are more specific... 300 points with at least 100 points in Psychology FOR EXAMPLE. they can also ask for a certain number of a levels (for example, must have 280 points from at least 3 a levels)
2. What subjects they look for - they may want you to do some subjects in order to get an offer. My biology courses i look at sometimes ask for chemistry or maths, as this will help even though the subjects arent the same.
3. what gcse's they require - this is never usually as specific as a levels, and is usually just FOR EXAMPLE 5 gcse's including C in English and Maths.
So its all about the research really. If youre in year 12, you will be applying next year and have plenty of time/support next year to do this. It all depends on relevance too. Science doesnt really have much to do with law so chances are they wont really care about science grades