Good biology textbook

Hello there, I would actually discourage using a textbook as most of them contain lots of waffle and don't use the wording included in mark schemes so if you make notes on this content only, you might drop some marks in exams.
I would recommend making notes on the specification itself as this contains exactly what you need to know - nothing more or less. At GCSE you will get lots of questions based on recall (just memorising a concept and writing it down) and if you revise exactly what the specification says, you will get free marks for these questions. I hope this helps!