Is it possible to redo the chemistry a level whilst retaking core 1 and core 2?

Hey, I want to do biomedical sciences and most of my courses require: AAA,AAB or ABB.
In my AS grades I got:
Biology:B-> 228 UMS
Maths: C-208 UMS so 2 points off a B
Chemistry: D-> 172 UMS

I was thinking of redoing chemistry and core 1 and core 2 to boost my grades.
I'm pretty secure in my understanding of core 1 and core 2 though.

Is this realistically possible or not?

It's possible to get an A or B for maths and biology without retakes in my opinion, you'll just have to work harder in your A2 year. I would advise against taking so many retakes, especially the maths ones where you already have a C grade.

If you're continuing to A2, it won't be possible to redo the whole of A-level chemistry. Even if your college or sixth form allow you to resit all the exams, it will take it's toll and you will struggle with the huge workload and stress of having twice the amount of exams. With your current set of grades, I would consider retaking one chemistry exam, presumably the one where you have the most amount of UMS available to get. I would advise against retaking 2 exams, since A2 exams are hard enough on their own without you having to worry about retakes.

Hope this helps

As someone who resat ALL their AS Chemistry units whilst doing A2 Chemistry, I think it's a struggle. Effectively you have twice the amount of exams which is very exhausting. I think if you're organised and have a solid understanding of chemistry (as in, you've gotta enjoy it!) you may be able to raise that grade slightly. But be wary that A2 Chemistry is much more difficult and if you focus too heavily on AS you may end up dropping some grades for your A2 exams. You could consider just retaking one of the exams and really making it the best it can be UMS wise.