Differences between GCSE and Advanced Subsidiary

Hello TSR,

I hope everything is going on well with everyone.
I am about to start my AS level and I will be considering to take the following subjects :

AS Biology
AS Chemistry
AS Physics
AS Mathematics

Its clear I am considering a medical school. However, regarding the science subjects above, how are they similar ( and different) to the GCSE versions ; particularly Edexcel board?


I still have my GCSE notes and considering to rehearse them if they will help me during my AS journey for these particular subjects.

If there are links to the AS specification for each of these subjects, please mention them as I will be too grateful for this.

Best Regards,
OmarEdExcel