The USMLE Step 1 is split into a variety of subdisciplines, similar to the curriculum of most medical schools. Within each subtopic, an attempt is made to test knowledge on "Normal Processes", "Abnormal Processes", Principles of Therapy" and "Psychosocial, cultural and environmental considerations". The basic disiciplines include topics in (the NBME uses different words to describe the topics, but the topics fall into these descriptions): biochemsitry and molecular biology, cell biology, genetics and development, pathology, psychiatry, physiology, pharmacology, microbiology, immunology, and statistics.
The NBME further specifies the topics to be tested within physiology, including systems biology (neurobiology, immunology, general physiology, etc.).
The USMLE Step 2 is broken into two distinct sections. The first section is designed to test your knowledge of the clinical fundamentals needed for the practice of medicine ("Clinical Knowledge", also known as USMLE Step 2 CK). Like any standardized test, it has its problems, but it tries to ensure that students are ready for the clinical part of their training.
The second part is USMLE Step 2 CS, or "Clinical Skills". This is a "live" exam in which you have 15 minutes to examine "Standardized Patients." The goal of this part of the exam is to determine if you have the basic skills in history taking and physical exam. This type of exam used to be limited to foreign medical graduates, but has been recently expanded so that all graduates must take the exam.
USMLE Step 1 Question Format
There is only one question format for USMLE Step 1: "Single question best answer".
USMLE Step 2 Question Format
All questions are multiple choice, but requiring either 1) best answer, 2) matching one-to-one, or 3) matching with more than one answer