Hi there, it depends on the semester. First semester there is a test approx every 3 weeks and the percentage is spread evenly. In addition you must pass your shelf to pass the class as well.

Second semester it is the same as the first. You are responsible for more classes and the classes are heavier in material so studying becomes a lifestyle.

I am in third semester presently and the material isn't quiet as heavy but the testing schedule is intense. We have a weekly quiz in Micro and a test about every three weeks. We will also be taking a lab test which is worth 20% of our overall grade. Pathology we have a test about every 2-3 weeks and the percentage depends on how much material we've covered. Behaviorial we have a test every 3 weeks or so. Immuno we have a test about every 2 weeks. Behaviorial and Pathology require you to do a presentation and Micro we have to do a group project/experiment.

Each of these, with the exception of Path, has a Shelf you must pass at the end of the semester. These are very good indicators of what the Step will entail. Pathology shelf will be given in 4th semester once all the material has been covered. I don't know much about 4th as I am not there yet. Hope this helped.