'Division of labour' is a term that describes the specialised functions of cell organelles which come together to ensure the cell is capable of surviving as well as performing it's role in the body. For example, beta cells in the pancreas are responsible for releasing insulin into the bloodstream. In order for the beta cells to release insulin, there must be an effective 'division of labour' in the cell. Firstly, the gene fo insulin undergoes 'transcription' in the Nucleus and the subsequent mRNA molecule leaves the Nucleus through nuclear pores. Ribosomes attached to the Rough ER then synthesise the insulin from the mRNA template (a process known as translation). The insulin proteins are then transported in vesicles to the golgi appartus, where they may be modified slightly with the addition of a carbohydrate, or simply packaged into vesicles once again. The insulin is then navigated in the vesicles to the plasma membrane of the cell, where it is secreted via exocytosis.
This example of division of labour shows how the Nucleus, ribosomes, Rough ER, vesicles and Golgi apparatus work in tandem to perform an essential metabolic function of the pancreas, however all organelles are involved in the division of labour within a cell as each organelle performs some kid of vital function needed for the survival of the cell as a whole.