Not knowing what a linked list is, is like a math major not knowing what an integral is. It is a super basic data structure and an integral data structure to a whole family of functional languages. A computer scientist right out of university should at least have heard of the basic data structures used in computer programs.

Even if you don't know how to implement them you at least need to know how they work and their performance characteristics. I would not expect them to be able to implement one in C but at least they should what the fuck it is.