Apostrophes where they don't belong?

Took a test in micro today. Thought I was doing pretty well, up until about question 38 ~ then I just hit a wall. Should have READ chapter 8. There was a lot of questions about plasmids and stuff... oh I was so lost. Didn't know just how lost I was until I was talking to Coots after the test. There were all these questions about F+ and F- & F' .... I was calling the last one "F apostrophe" ... Apparently it's "F prime". Yeah, that's how lost I was. Whoops.