All schools will require you to take at least one year of biology courses, including the lab work associated with it. Many potential medical students major in biology, taking many additional classes in this discipline.
General chemistry involves all the chemicals of the world. You would have been introduced to these concepts in your high school chemistry class. You'll need one year of general chemistry, including labs, to be admitted to medical school.
Organic chemistry is more detailed than general chemistry. It focuses on chemical compounds that contain carbon. You'll also need a year of courses in organic chemistry, including lab work.
In you are required one year of physics studies, you'll learn about matter and energy and how they interact. This includes motion, light, gravity and electronics, among other things.
English is not a requirement for all medical schools, but some require it. The MCAT tests verbal reasoning and writing skills, so it's good to have a class or two under your belt. Your English class doesn't always have to be a general class; you can often find an English class on a topic that you might enjoy, such as "Images of Death in Literature."
Only a quarter of medical schools require you to take calculus, but it may be necessary for some physics classes. It's a high level of mathematical study, focusing on how things change.