No comparison. It's completely different. The depth and the breadth of Step I blows away the MCAT. The MCAT tests your general knowledge in Physics, Chemistry, Biology, and reading comprehension. That's pretty much it.
Step I is the first part of one's license to practice medicine in the U.S. and tests the foundation of your medical science knowledge by covering Biochemistry, Anatomy, Histology (with Embryology thrown in there), Neuroanatomy (yes, arguably a completely separate subject from just plain old Anatomy), Physiology, Medical Microbiology, Immunology, Pathology, Behavioral Science, Epidemiology, and - of course you can't forget - good ole Pharmacology. (Did I miss anything?) It's 7 hours long and it is a bear. Don't let anyone tell you differently.
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