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This chain of electron acceptors is known as an electron transport chain. When this chain reaches PSI, an electron is again excited, creating a high redox-potential. The electron transport chain of photosynthesis is often put in a diagram called the Z-scheme, because the redox diagram from P680 to P700 resembles the letter Z. [3]
Anaerobic respiration is used by microorganisms, either bacteria or archaea, in which neither oxygen (aerobic respiration) nor pyruvate derivatives (fermentation) is the final electron acceptor. Rather, an inorganic acceptor such as sulfate (SO 2− 4), nitrate (NO − 3), or sulfur (S) is used. [16]
This enzyme mediates the final reaction in the electron transport chain and transfers electrons to oxygen and hydrogen (protons), while pumping protons across the membrane. [42] The final electron acceptor oxygen is reduced to water in this step. Both the direct pumping of protons and the consumption of matrix protons in the reduction of oxygen ...
The light excites an electron in the pigment P680 at the core of photosystem II, which is transferred to the primary electron acceptor, pheophytin, leaving behind P680 +. The energy of P680 + is used in two steps to split a water molecule into 2H + + 1/2 O 2 + 2e - ( photolysis or light-splitting ).
The electron transport chain comprises an enzymatic series of electron donors and acceptors. Each electron donor will pass electrons to an acceptor of higher redox potential, which in turn donates these electrons to another acceptor, a process that continues down the series until electrons are passed to oxygen, the terminal electron acceptor in ...
The electron accepting power of an electron acceptor is measured by its redox potential. [2] In the simplest case, electron acceptors are reduced by one electron. The process can alter the structure of the acceptor substantially. When the added electron is highly delocalized, the structural consequences of the reduction can be subtle.
A is the electron acceptor. Therefore, in light, the electron acceptor is reduced and oxygen is evolved. Samuel Ruben and Martin Kamen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water. Melvin Calvin works in his photosynthesis laboratory.
Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O 2). Although oxygen is not the final electron acceptor, the process still uses a respiratory electron transport chain. [1] In aerobic organisms undergoing respiration, electrons are shuttled to an electron transport chain, and the final electron ...