Stoichiometry of O2 consumption and ATP synthesis…
Because the energy of substrate oxidation drives ATP synthesis in ..
the source of energy for the synthesis of ATP from ..
Compounds called uncouplers, were found to collapse the pH gradient by shuttling protons back across the membrane through the compounds. One such uncoupler is dinitrophenol. In the presence of uncoupler electron transport continues but no ATP synthesis occurs.
If I understand what Dr. Martin is saying here, eukaryotes arose in "anoxic and sulfidic times" and we should not be surprised that "diverse eukaryotic lineages have retained oxygen-independent forms of mitochondrial ATP synthesis", on which those taxa formerly known as Archezoa once again must rely.
The Gibbs free energy of ATP synthesis ..
Uncoupling of electron transfers and ATP synthesis is useful to an organism. Such uncoupling can generate an energetically wasteful by-product as heat. This occurs normally in many hibernating animals, in newborn humans and in mammals adapted to the cold. It occurs in a specialized tissue known as brown adipose tissue. An uncoupling protein called thermogenin can accomplish this uncoupling and thus allow heat to be generated.
The Electron Transport Chain and the ATPase are asymmetrically oriented in the inner mitochondril membrane. An asymmetric orientation is a requirement to establish a p H gradient. A random arrangement would not result in a net gradient of protons and therefore no proton motive force for the synthesis of ATP.
chemiosmotic synthesis of atp in photophosphorylation
Peter D. Mitchell proposed the chemiosmotic hypothesis in 1961. The theory suggests essentially that most ATP synthesis in respiring cells comes from the electrochemical gradient across the inner membranes of mitochondria by using the energy of NADH and FADH2 formed from the breaking down of energy-rich molecules such as glucose.
A theory postulated by the biochemist Peter Mitchell in 1961 to describe ATP synthesis by way of a proton electrochemical coupling. According to this hypothesis proton motive force was responsible for driving the synthesis of ATP. In this hypothesis, protons would be pumped across the inner mitochondrial membrane as electron went through the Electron Transport Chain (ETS). This would result in a proton gradient with a lower pH in the inter-membrane space and an elevated pH in the matrix of the mitochondria. An intact inner mitochondrial membrane, impermeable to protons is a requirement for this model. The proton gradient and membrane potential are the proton motive force i.e. holds to derive ATP synthesis. pH gradient act as a battery, which stores energy to produce ATP. Over the past several years, Mitchell’s chemiosmotic hypothesis has been widely accepted as the mechanism of coupling of electron transport and ATP synthesis. He was awarded the Nobel Prize in chemistry in 1978. His comprehensive review on chemiosmotic coupling known as Grey book has been reported here with permission to offer milestone record and easy access to this important contribution to the biochemical literature. This acceptance by the scientific community is a result of accumulating experimental evidence supporting hypothesis.
Chemiosmotic theory and ATP synthesis
Chemiosmotic mechanism of atp synthesis | scholarly …
09/03/2016 · The majority of ATP synthesis is usually associated with respiratory ..
Chemiosmotic mechanism of atp synthesis
Depiction of ATP synthase using the chemiosmotic proton gradient to power ATP ..
Describe the ATP molecule and its function within ..
Several kinds of evidence support the chemiosmotic theory of ATP synthesis in chloroplasts
Primordial Soup Theory - Crystalinks
In the 1960s, the ideas of cell function and electron transfer were generally known, but there were no specifics or mechanisms that had been discovered or theorized about at the time. Having electron transfer coupled to ATP synthesis through oxidative phosphorylation and photophosphorylation was unknown. Several hypotheses existed, but before Mitchell, most looked at a direct chemical interaction.
Inhibition of oxidative phosphorylation | Biochemistry …
This energy found within the electrons is then used to pump protons throughout the mitochondrial matric to store energy. The protons then move back across the membrane through the ATP synthase enzyme. This energy forms with inorganic phosphates to synthesize ATP. As a final step, the protons and electrons at the last stop of the electron transport chain are taken up by oxygen molecules and this forms water.
Photosystems I and II - Encyclopedia Britannica
In 1961, Mitchell proposed what would be called the chemiosmotic hypothesis. It is a theory which states that adenosine triphosphate, or ATP, synthesis in a respiring cell comes from the electromechanical gradient that is found across the inner membrane of mitochondria. It uses the energy of nicotinamide adenine dinucleotide (NADH) and the Flavin group, which is a group of organic compounds that is based on pteridine.
Chemiosmotic Theory - Reference Module in …
Several laboratories had been performing extensive research on the subject, but no experimental evidence of the hypotheses that were generally accepted at the time could be produced. When Mitchell proposed that ATP synthesis was based on an indirect interaction between oxidizing and phosphorylating enzymes, and with ongoing research, the basic postulates from his original hypothesis turned out to be correct.
Chemiosmotic theory - definition of Chemiosmotic theory …
It can be said that chemiosmosis requires a membrane, a proton pump, a proton gradient and ATPase. Energy is utilized to pump protons across a membrane to create a gradient or protons within the thylakoid membrane. ATP ase has a channel, this channel allows diffusion of protons back across the membrane. The diffusion of protons release enough energy to activate ATPase enzyme. The ATPase enzyme catalyzes the formation of ATP, NADPH and the ATP is used in the biosynthesis reaction which takes place in the stroma. This reaction is responsible for fixing CO2 and for the synthesis of sugars.
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