Eukaryotic cells contain membrane-bound organelles, including a nucleus. Eukaryotes can be single-celled or multi-celled, such as you, me, plants, fungi, and insects. Bacteria are an example of prokaryotes. Prokaryotic cells do not contain a nucleus or any other membrane-bound organelle.
Another key difference is where the DNA is.
Eukaryotes store DNA in the nucleus, but prokaryotes e.g bacteria have their DNA in the cytoplasm