I think those kinds of topics could show up on the test, but not in a form that you're required to have a strong background knowledge in. So, it would provide the information to you in the passage. However it would not hurt to be familiar with the concepts in EM so that you're not knocked out of your comfort zone when you come across a such passage.
For more info, refer to AAMC's MCAT Interpretative manual... they have a list of topics that the MCAT covers. Generally if you don't see it on the list, you're not expected to know it outright... but you may still see it in a passage.