The ribosomes found in chloroplasts are similar to those in prokaryotes—and not to those in in plant cytoplasm. This supports endosymbiont theory, which, in part, states that mitochondria and chloroplasts were once prokaryotes that were engulfed by larger cells. read more
The 80s ribosomes are found in cytoplasm, whereas 70s types are found in mitochondria and chloroplasts. The 70s type are smaller and 80s are little larger. However, prokaryotes contain only one kind of ribosomes i.e. 70 type. read more