I was in the same situation a few months ago, a doc wanted my cv and I had no idea what it was, but I got some help with it from my schools career department. It is like a resume, but you include different things, academics and things that would be related to pursuing a career in medicine. Here is what I included:
objective: you want to be a doc...
education:
-when you will graduate
-major/minor
-gpa
-honors, dates you've been on dean's list etc
Relevant coursework:
-list science courses, in categories (bio, chem, physics, math etc)
-I also would list any courses you've taken to obtain a certification (CNA, EMT)
-if you've gone abroad with your school put it here
Undergrad research:
-if you've done it list it with a short description
pre-professional experience: (if you can think of a better title use it, this is the best one we could think of)
-shadowing
-experience with docs etc
Relevant experience:
-jobs you've had that relate to medicine, science, ex: lab jobs, tutoring
-volunteering
-clubs
-extracurricular stuff
The career advisor told me to highligh/bold the positions I held (ex: Tutor) because it makes it easy for them to quickly look at it an eaily get a sense of what you've done. Besides this the format is just like a resume. The only difference from a resume is that you just don't include every job that you've had since junior high (retail jobs etc), my advisor looked it over and told me not to include things from high school if they are minor (shadowing -yes include!)
Hope this helps! good luck