Which organelles are involved in photosynthesis and may support endosymbiotic theory?

Chloroplasts are the organelles responsible for photosynthesis in plants and some protists. They capture light energy and convert it into chemical energy through the process of photosynthesis, producing glucose and oxygen as byproducts. Chloroplasts contain chlorophyll, the green pigment crucial for this light-absorbing process, and they have their own DNA, which is similar to bacterial DNA.

The connection to the endosymbiotic theory lies in the evolutionary history of chloroplasts. This theory suggests that chloroplasts originated from free-living prokaryotic organisms, specifically cyanobacteria, that were engulfed by ancestral eukaryotic cells. Over time, a symbiotic relationship developed, with the eukaryotic host providing protection and resources to the engulfed cyanobacteria, which in return provided energy through photosynthesis. This theory is supported by the presence of their own circular DNA, double membranes, and similarities in ribosomal RNA to prokaryotes, all of which indicate that chloroplasts may have once been independent organisms before becoming integrated into plant cells.