The nucleus houses the DNA that contains the majority of a eukaryotic genome in the form of chromosomes. Prokaryotes do not have a nucleus. It should be noted, however, that eukaryotes also have DNA...
I am not exactly sure, but i think organelles made when a cell is made, or reproduced. Organelles are a nesscesity of cells and just come when a cell is made.
Usually organelles are not repaired when they are broken. They simply get digested and recycled by the lysosome because the cell can always make more of a certain organelle.