Hint: Bacteria are single-celled organisms that are tiny in size. Bacteria can be found almost anywhere on the planet and are essential to the planet's ecosystems. Some organisms can survive in extreme temperatures and pressures.
Complete answer: Bacteria are able to produce energy from sun rays and have a similar process to that of plants. Photosynthetic bacteria use bacteriochlorophyll and carotenoids to obtain light energy for chlorophyll. Electron transfer and photosynthesis reactions occur at a cell membrane in photosynthesis units; these structures are located in intracytoplasmic membranes as in vesicles Stacked together in single pairs which increase the surface of light absorption.
Moreover, photosynthesis bacteria show great plasticity, are able to adapt to constant change in lighting condition, able to rearrange the composition and concentration of pigment and consequently the absorption spectrum.
These bacteria are able to perform their own photosynthesis so these are known as photoautotrophs but some are also called as chemoautotrophic or photoheterotrophic. Chemoautotrophic organisms obtain energy by oxidation of electron donors in the environment, photoheterotrophs are heterotrophic organisms that can use light for energy but cannot use carbon dioxide as a source of carbon. These include purple bacteria, green non-sulphur bacteria, green sulphur bacteria, and cyanobacteria.
Note: On the basis of generation of photosynthesis organisms can be divided into Oxygenic and anoxygenic. Oxygenic photosynthesis organisms include eukaryotes and prokaryotes as plant photosynthesis protest cyanobacteria and anoxygenic includes photosynthesis organisms as are Green and Purple photosynthetic bacteria.