Can I take APM exam without PM knowledge?

The assumption is that if you have been exempted from studying and sitting the PM exam then you acquired PM knowledge elsewhere - to justify the exemption. If you really have no PM knowledge of any kind, then APM will be very difficult. I suggest you start studying APM and if you find that for a topic of question you lack PM knowledge then you can always look at the appropriate notes and lectures in our PM material.

Yes, indeed. But you must practise lots of questions.