Hill reaction
The Hill reaction was discovered by the biochemist Robin Hill from the University of Cambridge in 1937. The Hill reaction is the light-driven transfer of electrons from water to Hill reagents (non-physiological oxidants) against a chemical potential gradient. The Hill reaction demonstrated that oxygen O2 is produced in plants in a process that is separate from the process that converts carbon dioxide (CO2) to sugars. Hill's observation made a basic underlying refinement to our modern understandings of the process of photosynthesis.
The evolution of oxygen during the light-dependent steps in photosynthesis (Hill reaction) was proposed and proven by the British biochemist Robin Hill. He demonstrated that isolated chloroplasts would make oxygen (O2) but not fix carbon dioxide (CO2). This is evidence that the light and dark reactions happen in different places within the cell.
The Hill reaction of photosynthesis was discovered by Robin Hill (1937). He found that isolated chloroplasts from plants can release oxygen when they are illuminated by sunlight in the presence of a suitable electron acceptor such as ferricyanide. To demonstrate the Hill reaction in the laboratory dichlorophenolindophenol (DCPIP) was used as the terminal electron acceptor, replacing NADP which was not available due to the extraction of the chloroplasts from the plant cellular environment. The ferrocyanide is reduced (just as NADP is when the chloroplast is in vivo) while water (H2O) is oxidized into oxygen (O2) and hydrogen cations during the reaction. By using this technique to observe the reaction, Hill revealed a variety of valuable facts about photosynthesis. The Hill reaction confirms that oxygen (O2) is produced by a reaction that is separate from carbon dioxide (CO2) fixation. The reaction in which oxygen is released requires light; therefore the Hill reaction can be described as the light dependent reaction of photosynthesis. The reaction in which oxygen is released takes place within the chloroplast of plants and the Hill reaction demonstrated that the release of oxygen (O2) is only a partial reaction which requires one step of photosynthesis.
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