No! there is no minimum marking in each subject. Only your total score is looked into. However when 2 or more students have the same score their rank is given according to their scores in individual subjects. 

More preferance is given to Biology followed by chemistry then physics. 

Hey.

There is no such criteria for minimum marks in each subject to get admission in a government medical college through NEET. Your overall score should be good enough according to the cut off. You would require an overallscore of atleast 500 to get admission under the State quota and above 560 under the All India quota. This is an approximate score which would vary from state to state. 

Best of luck!