Do you think the exams dont test you on things they asked in the practice exam?

I feel like I’ve seen a pattern especially in science courses, where they give you a practice exam, but the actual exam barely tests you on the topics mentioned in the practice. Not sure if they do this so they make you study the whole thing but I’ve got the final coming up in 2 days and theres way too much memorizing to do. Would it be wise to kind of gloss over what was mentioned in the practice exam and focus more on topics that wasn’t in the exam lol