Organelle

An organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid membrane. The name organelle means little organ and comes from the idea that these structures are to cells what an organ is to the body.

There are many types of organelles, particularly in the eukaryotic cells of higher organisms. Some of them are separated from the rest of the cell by lipid layers similar in structure to the cell membrane. Major eukaryotic organelles are the Golgi apparatus, mitochondrion, chloroplast, endoplasmatic reticulum, vacuole, and nucleus.