Do Universities Care About Grades Before Sixth Form?

Hi guys,

I'm currently having exam week and just did horribly in an exam that was confusing and slightly badly written, and I wanted to ask if Oxbridge universities care about your grades before Sixth Form if it's just your own school's system (i.e. not GCSEs or any kind of international qualifications)? Especially if you don't have perfect A grades in subjects that have absolutely no relation to what you're planning to pursue at university? Like biology and law.

Thanks!

You don't need to upload them to UCAS?

Sorry, the American system involves all of your high school results, so I was kind of assuming the same would go for the UK

But what if you're studying abroad before Sixth Form in a country that doesn't do GCSEs or any sort of official international qualification?

Do you take any official external exams? If so, what and when?

No, we don't. I'm in the international division of a public school that sort of follows an American curriculum (main difference is the difficulty in science subjects and the workload in general), so we do it like the Americans (i.e. only official examinations in the last two years of high school like IB and AP).