What is the difference between "end up" and "end"?
That is a good question, but it is rather broad. When asking about differences between words and phrases, it is good to provide or attempt to provide example sentences in which the difference between them is unclear to you.
"End" can, of course, be used as a noun, as in "The credits are given at the end of a movie"; however, since "end up" can only be used as a verb group, I assume that you mean to refer to "end" as a verb. Let's contrast them with examples:
(1a) The movie has ended.
(1b) *The movie has ended up.
(2a) I ended up liking the movie.
(2b) *I ended liking the movie.
(3a) There ended up being fifteen people in the class.
(3b) *There ended being fifteen people in the class.
You can see from those examples that "end" and "end up" behave quite differently. The basic difference is that "end" means "conclude" or "terminate," "end up" is a so-called raising verb group like "wound up" or "happened to be":
(2a') I wound up liking the movie.
(3a') There happened to be fifteen people in the class.