With this resolve in mind, I am determined to leave no stone unturned in the path to fulfilling my dream. At UC Berkeley, I have explored different opportunities and took on many challenges to best prepare myself for medical school, including pursuing a double major in Molecular Immunology and Integrative Biology. As a student of science, I am most interested in applying knowledge from the classroom into hands-on research to answer scientific questions.
Great personal statement! I love it! This is the type of doctor who becomes a healer, not just a physician. Two suggestions about this paragraph:
(1) The second sentence would be better if the verb tenses matched: i.e. ...I have explored different opportunities and have taken on .... OR ...I explored different oportunities and took on.... If you are no longer at UC Berkeley just use the past tense here
(2) change the preposition--not into but to "applying knowledge from the classroom to hands-on research..."
Best wishes on your medical career!