If a school chooses OCR Gateway Science, is it possible to allow students to take OCR Twenty First Century Additional Applied Science? or are the two suites totally separate?
Yes students can do OCR Twenty First Century Additional Applied Science if they are otherwise doing OCR Gateway Science.
The two suites are not totally separate.
OCR did not create a different GCSE Additional Applied Science course for Gateway Science because schools in the Twenty First Century Science pilot course were so pleased with its Applied Science. OCR had no hope of writing a equally good applied course for Gateway, so decided to offer the same Applied Science course in both suites.
See this guide to this Guide to the OCR website.