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Where does photosynthesis take place?

Carbon has two primary stable isotopes: and . is the famous unstable isotope used for dating recently deceased life forms, but testing carbon’s stable isotopes has yielded invaluable information. is the backbone of all of life’s structures, and life processes often have a preference for using carbon-12, which is lighter than carbon-13 and hence take less energy to manipulate. Scientists have been able to test rocks in which the “fossils” are nothing more than smears and determine that those smears resulted from life processes, as there is more carbon-12 in the smear than carbon-13 than would be the case if life was not involved. This has also helped date the earliest life forms. Life’s preference for lighter isotopes is evident for other key elements such as sulfur and nitrogen, and scientists regularly make use of that preference in their investigations.

is both a reactant &product of photosynthesis

In respiration energy is released fromsugars when electrons associated with hydrogen are transported to oxygen (theelectron acceptor), and water is formed as a byproduct. The mitochondriause the energy released in this oxidation in order to synthesize ATP. Inphotosynthesis, the electron flow is reversed, the water is split (not formed),and the electrons are transferred from the water to CO2 and in theprocess the energy is used to reduce the CO2 into sugar. Inrespiration the energy yield is 686 kcal per mole of glucose oxidized to CO2,while photosynthesis requires 686 kcal of energy to boost the electrons from thewater to their high-energy perches in the reduced sugar -- light provides thisenergy.

which is the end product of photosynthesis.

Now we need to understand how cells can use the products ofphotosynthesis to obtain energy.

About the time that the continents began to grow and began, Earth produced its first known glaciers, between 3.0 and 2.9 bya, although the full extent is unknown. It might have been an ice age or merely some mountain glaciation. The , and numerous competing hypotheses try to explain what produced them. Because the evidence is relatively thin, there is also controversy about the extent of Earth's ice ages. About 2.5 bya, the Sun was probably a little smaller and only about as bright as it is today, and Earth would have been a block of ice if not for the atmosphere’s carbon dioxide and methane that absorbed electromagnetic radiation, particularly in the . But life may well have been involved, particularly oxygenic photosynthesis, and it was almost certainly involved in Earth's first great ice age, which may have been a episode, and some pertinent dynamics follow.

In the earliest days of life on Earth, it had to solve the problems of how to reproduce, how to separate itself from its environment, how to acquire raw materials, and how to make the chemical reactions that it needed. But it was confined to those areas where it could take advantage of briefly available potential energy as . The earliest process of skimming energy from energy gradients to power life is called respiration. That earliest respiration is today called because there was virtually no free oxygen in the atmosphere or ocean in those early days. Respiration was life’s first energy cycle. A biological energy cycle begins by harvesting an energy gradient (usually by a proton crossing a membrane or, in photosynthesis, directly capturing photon energy), and the acquired energy powered chemical reactions. The cycle then proceeds in steps, and the reaction products of each step sequentially use a little more energy from the initial capture until the initial energy has been depleted and the cycle’s molecules are returned to their starting point and ready for a fresh influx of energy to repeat the cycle.

In which organelle does photosynthesis take place in plant cells

Some organelles are responsible for gathering cell energy, others for controlling cell activities.

The dates are controversial, but it appears that after hundreds of millions of years of using various molecules as electron donors for photosynthesis, began to split water to get the donor electron, and oxygen was the waste byproduct. Cyanobacterial colonies are dated to as early as 2.8 bya, and it is speculated that may have appeared as early as 3.5 bya and then spread throughout the oceans. Those cyanobacterial colonies formed the first fossils in the geologic record, called . At Shark Bay in Australia and some other places the water is too saline to support animals that can eat cyanobacteria, and give us a glimpse into early life on Earth.

Some bacteria use Photosystem I and some use Photosystem II. More than two bya, and maybe more than three bya, cyanobacteria used both, and a miraculous instance of innovation tied them together. were then used to strip electrons from water. Although the issue is still controversial regarding when it happened and how, that instance of cyanobacteria's using manganese to strip electrons from water is responsible for oxygenic photosynthesis. It seems that some enzymes that use manganese may have been "drafted" into forming the manganese cluster responsible for splitting water in oxygenic photosynthesis. Water is not an easy molecule to strip an electron from, a single cyanobacterium seems to have “stumbled” into it, and it probably happened only . Once an electron was stripped away from water in Photosystem I, then stripping away a proton (a hydrogen nucleus) essentially removed one hydrogen atom from the water molecule. That proton was then used to drive a “turbine” that manufactures ATP, and wonderful show how those protons drive that enzyme turbine (). Oxygen is a waste product of that innovative ATP factory.

This also allows the oxygen produced in photosynthesis to leave the leaf easily.
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(sugar produced during photosynthesis) however, respiration does ..

The process of transforming requires millions of years. When organic sediments are buried, most of the oxygen, nitrogen, hydrogen, and sulfur of dead organisms is released, leaving behind carbon and some hydrogen in a substance called , in a process that is . Plate tectonics can subduct sediments, particularly where oceanic plates meet continental plates. There is an “oil window” roughly between 2,000 and 5,000 meters deep; if kerogen-rich sediments are buried at those depths for long enough (millions of years), (which produce high temperature and pressure) break down complex organic molecules and the result is the hydrocarbons that comprise petroleum. If organic sediments never get that deep, they remain kerogen. If they are subducted deeper than that for long enough, bonds are broken and the result is , which is also called . Today, the geological processes that make oil can be reproduced in industrial settings that can in a matter of hours. Many hydrocarbon sources touted today as replacements for conventional oil were never in the oil window, so were not “refined” into oil and remain kerogen. The so-called and are made of kerogen ( is soluble kerogen). It takes a great deal of energy to refine kerogen into oil, which is why kerogen is an inferior energy resource. Nearly a century ago in it took less than one barrel of oil energy to produce one hundred barrels, for an energy return on investment ("EROI" or "") of more than 100, in the Golden Age of Oil. Global EROI is declining fast and will fall to about 10 by 2020. The EROIs of those oil shales and oil sands are less than five and as low as two.

Where does photosynthesis take place? - eschooltoday

Because of early Eocene Arctic forests, animals moved freely between Asia, Europe, Greenland, and North America, which were , and great mammalian radiations occurred in the early Eocene. Many familiar mammals first appeared by the mid-Eocene, such as , elephants, , and . The may have first appeared in Asia and migrated to India, Africa, and the Americas. Europe was not yet connected with Asia, however, as the separated them. Modern observers might be startled to know where many animals originated. and lived there for more than 40 million years, until humans arrived. Their only surviving descendants in the Western Hemisphere are . As with , or , or , or Eocene mammalian migrations via polar routes, the migrants often involuntarily “sailed” on vegetation mats that crossed relatively short gaps between the continents. Such a migration depended on fortuitous prevailing currents and other factors, but it happened often enough.

Where does photosynthesis take place

In an effort to keep up with the world’s growing energy needs, researchers.
What environmental cycle involves photosynthesis and respiration as What are the end products of photosynthesis?

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