Do you need to pass separately on both papers of the first MBBS RGUHS?

There is no need to pass separately on both the papers of a subject in the first year of MBBS RGUHS. You just need to make sure to score above 50% of the total that includes your internal examinations, both the papers and the theory viva. According to the RS3 regulations and the marks distribution, it is not mandatory. 

Internals carry 40 marks, total marks for both papers combined is 200 marks and the viva has 40 marks. So, the total becomes 280, out of which it is necessary for you to score above 140 to pass the subject. This holds true for the subjects- anatomy and physiology. As for biochemistry, only half of it will be applied to the subject.