AIIMS and JIPMER have been scrapped off in favour of NEET and not the other way round. So it is unlikely that NTA will change NEET's exam pattern. May be AIIMS and JIPMER will conduct theri separate admission process by conducting further rounds but NEET will not have a  changed exam pattern. This is because AIIMS has approximately 1500 seats and JIPMER 200 seats. But across India, almost  90,000 MBBS seats also are filled through NEET. So bringing in a change for 1700 odd seats is unlikely. As of now, NEET has 180 questions in the form of MCQs. Physics and Chemistry have 45 questions each and Biology has 90 questions. Every correct answer gives you 4 marks and a wrong answer takes away 1 mark.