Cell Membrane
The barrier that surrounds the contents of a cell and regulates the movement of substances in and out.

Centrosome
A structure composed of microtubules which distributes chromosomes during the process of cell division.

Cytoplasm
The gel-like material within a eukaryotic cell that contains all of the organelles.

Endoplasmic reticulum
Tubular network that transports molecules from one cell part to another. Participates in the synthesis of protein and lipid molecules.

Golgi apparatus
The Golgi packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination.

Lysosomes
The waste disposal system of the cell digests macromolecules, old cell parts and microorganisms.

Mitochondria
The powerhouses of the cell generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy.

Nucleus
Large structure enclosed in a nuclear envelope which contains nearly all the cell's genome (DNA).

Ribosomes
These organelles link amino acids together to build proteins.