A typical animal cell. Within the cytoplasm, the major organelles and cellular structures include: (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (6) Golgi apparatus (7) cytoskeleton (8) smooth endoplasmic reticulum (9) mitochondria (10) vacuole (11) cytosol (12) lysosome (13) centriole.

In cell biology, an organelle is a part of a cell that does a specific job.

Organelles typically have their own plasma membrane round them. Most of the cell's organelles are in the cytoplasm.

The name organelle comes from the idea that these structures are to cells what an organ is to the body.