Pre-Med Track: Bio or Microbiology

Hi, Any insight or feedback on the curriculum for bio vs. microbiology for undergrads interested in following a pre-med track? Are the research opportunities the same/plentiful? Are class selections varied for each major? Is the level of difficulty the same? Any pros/cons to majoring in either of these while on a pre-med track? Thanks for insight as it relates specifically to U-M-Ann Arbor.