Difference between a memory cell and a memory chip?
Old school: A memory cell holds one bit of information, a 1 or 0. A bit and a cell can be used interchangeably. Memory chips are made up of one or more cells. In modern hardware, memory chips contain millions or billions of cells.

Modern terminology: 8-bit per cell memory?

RAM, or Random Access Memory, is a type of memory that allows random access. RAM can be made up of one or more memory chips. Here's an example of some RAM: