Final answer:
The endosymbiosis hypothesis proposes that mitochondria and chloroplasts evolved within eukaryote cells through symbiosis with prokaryotic cells. Genetic evidence supports this theory, showing similarities between mitochondrial and chloroplast DNA and bacterial DNA, and the process of replication in these organelles.
Step-by-step explanation:
The endosymbiosis hypothesis proposes that mitochondria and chloroplasts evolved within eukaryote cells through a symbiotic relationship with prokaryotic cells. This hypothesis suggests that mitochondria and chloroplasts have their own DNA and evolved separately from the host cell's nucleus, but have since evolved in tandem with the host cell. Genetic sequencing and phylogenetic analysis support this theory, showing that mitochondrial and chloroplast DNA are highly related to bacterial DNA, and that these organelles reproduce through binary fission, similar to bacteria.