The nucleus controls the cell's activities and contains all the genetic material (46 chromosomes in humans).
The nucleolus is involved in the synthesis of ribosomal RNA. It is a dark body inside the nucleus.
The nuclear membrane keeps DNA inside the nucleus but allows mRNA and proteins through. It is a double membrane with large pores.
Ribosomes assemble proteins from RNA codes. They are found free-floating in the cytoplasm throughout the cell or attached to the endoplasmic reticulum.
The smooth endoplasmic reticulum is a series of long canals running throughout the cell. It detoxifies the cell and converts foodstuffs.
The rough endoplasmic reticulum is a series of long canals running throughout the cell with ribosomes attached. It transports proteins to the golgi bodies for packaging.
Golgi bodies (also apparatus or complex) store and package cellular secretions for export out of the cell (usually through the use of vacuoles). Salivary, oil, and digestive glands have very active golgi bodies.
Lysosomes digest and remove worn out cell organelles. In essence, they are vacuoles filled with digestive enzymes.