Biochemical pathways: what to memroize!?

For the biochemical pathways, are people just studying the precursors, end products, and major regulatory points? Or is it expected to know each step, like what comes off after OAA during Krebs cycle? Kinda lost here. I am not familiar at all with fatty acid metabolism so I do not know how to approach those especially. The Khan videos covers the entire sequence but my Princeton Review book says "dont worry about the details".

Thanks