Final answer:
The statement is true; mitochondria and chloroplasts likely originated from a symbiotic relationship with free-living bacteria, engulfed by early eukaryotic cells. This is known as the endosymbiotic theory.
Step-by-step explanation:
The statement is true. Mitochondria and chloroplasts are thought to have originated from a symbiotic relationship between early eukaryotic cells and free-living bacteria. This theory is known as the endosymbiotic theory. According to this theory, a larger host cell engulfed smaller bacterial cells through a process similar to phagocytosis. These bacteria were similar to present-day prokaryotes, and they eventually evolved into mitochondria and chloroplasts. This evolutionary step provided the host cells with advantages such as the capability for more efficient energy production in the case of mitochondria, and the ability to perform photosynthesis in the case of chloroplasts. Cell organelles like mitochondria and chloroplasts still retain some of their bacterial features, such as their own DNA and ribosomes, which supports the endosymbiotic theory.