redox

Examples of redox in the following topics:

• Wetland Soils

  • Nutrient cycling in lakes and freshwater wetlands depends heavily on redox conditions.
  • Redox potential, or reduction potential , is used to express the likelihood of an environment to receive electrons and therefore become reduced.
  • The oxidized environment has high redox potential, whereas the reduced environment has a low redox potential.
  • The redox potential is controlled by the oxidation state of the chemical species, pH and the amount of oxygen (O2) there is in the system.
  • This equation will tend to move to the right in acidic conditions which causes higher redox potentials to be found at lower pH levels.

• Electron Donors and Acceptors

  • In other words, they correspond to successively smaller Gibbs free energy changes for the overall redox reaction Donor → Acceptor.
  • Since electron transport chains are redox processes, they can be described as the sum of two redox pairs.
  • For example, the mitochondrial electron transport chain can be described as the sum of the NAD+/NADH redox pair and the O2/H2O redox pair.
  • The redox potential of the acceptor must be more positive than the redox potential of the donor.
  • The associated redox reaction, which is thermodynamically favorable in nature, is thermodynamically impossible under "standard" conditions.

• Oxidoreductase Protein Complexes

  • In biochemical reactions, the redox reactions are sometimes more difficult to see, such as this reaction from glycolysis: Pi + glyceraldehyde-3-phosphate + NAD+ → NADH + H+ + 1,3-bisphosphoglycerate.

• Proton Reduction

  • Biological energy is frequently stored and released by means of redox reactions, or the transfer of electrons.
  • In every redox reaction you have two halves: reduction and oxidation.

• Oxygenic Photosynthesis

  • Carbon fixation is a redox reaction, so photosynthesis needs to supply both a source of energy to drive this process, and the electrons needed to convert carbon dioxide into a carbohydrate, which is a reduction reaction.

• Shared Features of Archaea and Eukaryotes

  • In these reactions, one compound passes electrons to another (in a redox reaction), releasing energy to fuel the cell's activities.

• Respiration and Proton Motive Force

  • Chemically, cellular respiration is considered an exothermic redox reaction.
  • Most of these smaller reactions are redox reactions themselves.

• Energy Conservation and Autotrophy in Archaea

  • In these reactions one compound passes electrons to another in a redox reaction, releasing energy to fuel the cell's activities.

• Nitrate Reduction and Denitrification

  • The complete denitrification process can be expressed as a redox reaction: 2 NO3− + 10 e− + 12 H+ → N2 + 6 H2O.

• Two-Component Regulatory Systems

  • These pathways have been adapted to respond to a wide variety of stimuli, including nutrients, cellular redox state, changes in osmolarity, quorum signals, antibiotics, temperature, chemoattractants, pH and more.