You were faced with exactly the same issue that a teacher was, you were limited in the time and space you had, so you tried to focus on the basic concepts. You

You were faced with exactly the same issue that a teacher was, you were limited in the time and space you had, so you tried to focus on the basic concepts. You failed to capture all of the detail, because of those limitations. This is exactly why a teacher doesn't discuss DNA methylation in a Bio 101 course. When I'm just trying to grok DNA vs RNA, getting exposed to http://en.wikipedia.org/wiki/DNA_methylation http://en.wikipedia.org/wiki/DNA_methylation is not going to help me, it's just going to confuse me. But, if the teacher wanted to stretch the class a bit, perhaps diverting a bit of time to the intricacies of tRNA vs mRNA might make sense, and perhaps mention the existence of other biologically active RNAs. But, you have to draw a line somewhere, or you lose everyone. Bio 101 is a huge course, with thousands of concepts/terms to absorb. And the DNA component, with several dozen concepts, gets at most 1-2 hours of the curriculum. DNA methylation falls below the line.