What do you mean by semi - autonomous cell organelle ?
The organelles which contain their own DNA and can reproduce independently of the nucleus. They are said to be 'semi-autonomous organelles'
Chloroplast and mitochondria are called semi-autonomous organelles because they have their own genetic material (DNA) and are capable of synthesizing proteins required for their functioning.
These are the mitochondria and chloroplasts and it is because they have their own DNA, mRNA, tRNA, ribosomes and they replicate by binary fission so they are said to be self governing. Semi autonomous means they want to leave but they are in a symbiotic relationship with the cell and have evolved to become part of it.