1 Most cases of COPD, and therefore emphysema, are caused by cigarette smoking. 2  Emphysema is rarely caused by a congenital condition known as Î±1-antitrypsin deficiency, for which there is a lab test. 3  Shortness of breath and cough are the main symptoms of emphysema.
Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth.
exists and is an alternate of . Phototrophs are the organisms that carry out photosynthesis to acquire energy. They use the energy from sunlight to convert carbon dioxide and water into organic material to be utilized in cellular functions such as biosynthesis and respiration. Most phototrophs are autotrophs, also known as photoautotrophs, and can fix carbon. They can be contrasted with chemoautotrophs that obtain their energy by the oxidation of electron donors in their environments. Photoheterotrophs produce ATP through photophosphorylation but use organic compounds to build structures.