Well, the emphasis in medical school is clearly towards medical biochemistry, so it's a bit different in terms of material emphasis... However, I think the main difference between any undergrad class and medical school isn't necessarily more difficulty in terms of content, but it is the high rate of concurrent information transfer. The amount of information given to you per unit time is very, very large in magnitude. It borders on insanity at times, in my opinion. What takes you weeks and months to learn in a given undergrad class, you will often cover in 1 hr, or sometimes even less. Also, remember, you have many other medical school basic science subjects you are studying at the same time, going at approximately the same rate, and you are expected to cross-correlate between them. Furthermore, you are expected to know how to apply this information to clinical situations. I know that it sounds intimidating, but you get used to it. You become really good at deciding what is important and what is not.
