I realized that when you are first learning about them, a lot of folks (including myself) get the different parts and functions mixed up. I came up with some ways to remember -- they might not work for you, but at least if you read this, you will have a hearty laugh at my attempt to help. =)

Cell Membrane: Re-memberane that the membrane is barrier-y good at controlling what comes into and out of a cell!
Nucleus: When someone is "NU" (new), then you direct them to different places, like the nucleus does!
MitochondriA: Mitochondria are mit-y (mighty) "powerful" in the way they produce energy.
Ribosomes: Ribosomes are like "ribs" (the ones you eat) because you can get proteins from them!
Cytoplasm: In the gel of the cytoplasm, the cell organelles are a great "cyt" (sight) to see!
Chromosomes: Chromosomes are condensed chromatin that carry commands and control characteristics.

Well, there you go! I hope that helped (or at least cheered up your day)! See ya around!

~Ultrachic~