chloroplasts are the source of oxygen inside the plant during photosynthesis.
chloroplasts are the source of oxygen inside the plant during photosynthesis.
what is the source of oxygen inside the plant during photosynthesis?
chloroplasts
the main source of oxygen in the atmosphere is oxygenic photosynthesis, and its first appearance is sometimes referred to as the oxygen catastrophe. geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the paleoproterozoic era around 2 billion years ago. modern photosynthesis in plants and most photosynthetic prokaryotes is oxygenic. oxygenic photosynthesis uses water as an electron donor, which is oxidized to molecular oxygen () in the photosynthetic reaction center.









































timeline of photosynthesis on earth 









































section::::symbiosis and the origin of chloroplasts.
evolution of photosynthesis
dissolved oxygen and dissolved carbon dioxide are often discussed together due their coupled role in respiration and photosynthesis. dissolved oxygen concentrations can be altered by physical, chemical, and biological processes and reaction. physical processes including wind mixing can increase dissolved oxygen concentrations, particularly in surface waters of aquatic ecosystems. because dissolved oxygen solubility is linked to water temperatures, changes in temperature affect dissolved oxygen concentrations as warmer water has a lower capacity to "hold" oxygen as colder water. biologically, both photosynthesis and aerobic respiration affect dissolved oxygen concentrations. photosynthesis by autotrophic organisms, such as phytoplankton and aquatic algae, increases dissolved oxygen concentrations while simultaneously reducing carbon dioxide concentrations, since carbon dioxide is taken up during photosynthesis. all aerobic organisms in the aquatic environment take up dissolved oxygen during aerobic respiration, while carbon dioxide is released as a byproduct of this reaction. because photosynthesis is light-limited, both photosynthesis and respiration occur during the daylight hours, while only respiration occurs during dark hours or in dark portions of an ecosystem. the balance between dissolved oxygen production and consumption is calculated as the aquatic metabolism rate.
limnology