I hope I know right: Mitochondria, chloroplast, chromoplast and leucoplast have their own DNA so they can reproduce themselves when needed. Let’s say a cell is having a mitotic division. How do both 2 cells have endoplasmic reticulum for instance? Or ribosome? (I understand lysosome and tonoplast, they are crude.) [Maybe my question is nonsense, please tell me why it’s nonsense, thank you.]
I’m new here and I’m passionate about Biology. I try to learn by searching and explaining to others. So, maybe I do some mistakes, so don’t hesitate to let me know. Also, I’m french and I fear that my sentences maybe be too strange for a English natural speaker. Excuse me if I use the wrong words, etc.
In fact, not all organelles are supposed to have their own DNA to be organelles. Some are coded by the Nucleus DNA because evolution brings the cell to synthesize its own tools.
Endosymbiotic theories tell us that some cells might become a part of other cells and, because it’s an advantage in some environment, this co-working continues to exist. Nucleus DNA can’t code these type of other cells that we, over time, call organelles.
Now, how can this type of cell stay an organelle of other cells through time ? Because during fertilization, organelles that already exists become part of the “new cell” and, after that, cell division and other stuffs…