Keep chemistry. Most biology degrees want it.
I'd drop maths- I found it rate hard though so I'm biased :')
If you really love german then keep it and don't do chemistry, but be aware that it will limit what biology degree you can apply for.
A boy in my year did chemistry edexcel in one year, but trust me you'll end up with a lot of extra stress- chem is very difficult as it is so I'd try and avoid doing that!