The basic unit of life is essentially the cell. A cell membrane surrounds all the cells. The cell membrane is thus semi permeable hence this allows certain substances to pass and blocking others into the cell. This cell membrane is composed of phospholipids that are a double layer embedded in proteins. Plant cells on their part contain an additional layer called cell wall that surrounds them. An organelle in cell biology is actually a specialized subunit or structure, which is found within a cell and has a specific function. Therefore, a cell organelle refers to a membrane bound structure or compartment in a cell which performs a certain special function. There are various types of cell organelles in both plant and animals.
The nucleus is in fact the most well-known and easily stained cell organelle. This cell organelle has two functions that are important. It is the organelle that contains the cell hereditary information. This means that all the metabolism, species behavior, and development instructions are actually found in DNA within this cell organelle. In its role as carrier and guardian of genetic information, this cell organelle is capable of preparing the information extract duplicates for its transmission to the new generation of the cell. Secondly, nucleus possesses the machinery for controlling a range of cellular activities. It actually does this through directing the enzymes synthesis.
The other type of cell organelles is mitochondria. These are essentially complex energy producing organelles that are found in each eukaryotic cell. Therefore, the function of mitochondria is to produce the chemical energy that is usable by the cells. They are enclosed in the double membrane; possess their circular DNA and ribosome. In addition, they transfer RNA together with the other protein synthesis machinery.
If the cells in nucleus organelle took over all the duties of mitochondria organelle, the organisms will not survive because as stated, each organelle cells in an organism performs specific functions which can not be performed by the other cells.
Mullins, Christopher (2004). "Theory of Organelle Biogenesis: A Historical Perspective". The Biogenesis of Cellular Organelles. Springer Science Business Media, National Institutes of Health. ISBN 0-306-47990-7.