I took undergraduate genetics at my current university (large school) as an elective while getting my masters in statistics about two years ago. I had not taken any biology since getting a 4 on the AP Exam back in 1997, so it was my first biology class in 8 years.
I think my professor was about average in terms of difficulty (not too hard but not too easy). We had four tests and a final. On the first three tests I hovered right around the 90 mark (and the professor made 92 an A, 90-91 A-). But on the fourth test, which was about microbiology and molecular genetics, I pulled a 92.5 while the average was 67. For the other tests, the other averages were somewhere in the 70s. Since 67 is a D instead of a C (and his goal was to make the average score a B- after average in homework points), he curved by 8 points. And that gave me a 100.5, boosting my grade all the way into the middle range of the A's by one test! And the final was just rehashing the other four tests, with a little bit of new material thrown in.
I pulled a solid A in the end, and did best on the microbiology part of the class without ever haven taken micro, while many of my classmates were biology majors and took that.
Moral of the story: depends upon professor and also you. I did not take any biology in 8 years (since AP Biology in high school in my sophomore year), and I considered this class medium difficulty. But I still pulled a solid A.
I am sure biochem / organic (which I have never taken) is much harder.
And I took the lecture part of Chem II six years ago during a six-week summer session at a community college that I was attending then. I barely pulled an A and studied VERY hard, while Chem I was a total breeze for me at that time. But that might be because it was 6 week session and a whole semesters worth of material. It looked like 20 people were in the class at the CC and only 3 pulled A's, but one guy was always scoring much higher than me! So that was always frustrating, because he just seemed to "get it" better. If I ever needed to study general chem again, I would have to review everything since I do not use it in my current PhD field of study.
Again, as shown in this example, CC is not always easy, although it also could be very easy!