If you were writing a resume after changing careers, how would you choose

[wannabedrt]

which format to use? I will be graduating in May and one of my classes requires a written resume. My previous jobs include restaurant management, hospital unit clerk, telemetry monitor on the cardiac ward, and HR manager. My future career will be as a physician, however the job I am to focus on for the assignment would be related to a bachelor's degree in biochemistry.
Would it be better to focus on specific abilities from these jobs or to continue with a chronological format. Also, should I focus on the classes I have taken to prepare for my degree such as labs and neglect job history or should I include job history and just do a basic overview of my college preparation. Is it necessary to include grade point and test scores (MCAT)? Thanks for any advice you could pass on to me.