calvin cycle

Examples of calvin cycle in the following topics:

• Regulation of the Calvin Cycle

  • The Calvin cycle is a process that ensures carbon dioxide fixation in plants.
  • The Calvin cycle is a process utilized to ensure carbon dioxide fixation.
  • During the first phase of the Calvin cycle, carbon fixation occurs.
  • During the second phase of the Calvin cycle, reduction occurs.
  • An overview of the Calvin cycle and the three major phases.

• Intermediates Produced During the Calvin Cycle

  • The Calvin Cycle involves the process of carbon fixation to produce organic compounds necessary for metabolic processes.
  • The Calvin Cycle is characterized as a carbon fixation pathway.
  • The Calvin Cycle is also referred to as the reductive pentose phosphate cycle or the Calvin-Benson-Bassham cycle.
  • The following is a brief overview of the intermediates created during the Calvin cycle.
  • Outline the function of the intermediates produced in the major phases of the Calvin Cycle

• Biosynthesis and Energy

  • The major pathways utilized to ensure fixation of carbon dioxide include: the Calvin cycle, the reductive TCA cycle, and the acetyl-CoA pathway.
  • The Calvin cycle involves utilizing carbon dioxide and water to form organic compounds.
  • The reductive TCA cycle, commonly referred to as the reverse Krebs cycle, also produces carbon compounds from carbon dioxide and water.

• Carboxysomes

  • These compartments are thought to concentrate carbon dioxide to overcome the inefficiency of RuBisCo (ribulose bisphosphate carboxylase/oxygenase) - the predominant enzyme in carbon fixation and the rate limiting enzyme in the Calvin cycle.

• Energy Conservation and Autotrophy in Archaea

  • For example, archaea use a modified form of glycolysis (the Entner–Doudoroff pathway) and either a complete or partial citric acid cycle.
  • This process involves either a highly modified form of the Calvin cycle or a recently discovered metabolic pathway called the 3-hydroxypropionate/4-hydroxybutyrate cycle.
  • In addition, the Crenarchaeota use the reverse Krebs cycle while the Euryarchaeota use the reductive acetyl-CoA pathway.

• Nitrification

  • Nitrobacter plays an important role in the nitrogen cycle by oxidizing nitrite into nitrate in soil.
  • Nitrification is an important step in the nitrogen cycle in soil.
  • Electron and proton cycling are very complex, but as a net result only one proton is translocated across the membrane per molecule of ammonium oxidized.
  • As in sulfur and iron oxidation, NADH for carbon dioxide fixation using the Calvin cycle is generated by reverse electron flow, thereby placing a further metabolic burden on an already energy-poor process.
  • The importance of bacteria in the cycle is immediately recognized as being a key element in the cycle, providing different forms of nitrogen compounds assimilable by higher organisms.

• Iron Oxidation

  • Like sulfur oxidation, reverse electron flow must be used to form the NADH used for carbon dioxide fixation via the Calvin cycle.

• Habitats and Energy Metabolism of Crenarchaeota

  • Many basic metabolic pathways are shared between all forms of life; for example, archaea use a modified form of glycolysis (the Entner–Doudoroff pathway) and either a complete or partial citric acid cycle.
  • This process involves either a highly modified form of the Calvin cycle or a recently discovered metabolic pathway called the 3-hydroxypropionate/4-hydroxybutyrate cycle.
  • The Crenarchaeota also use the reverse Krebs cycle while the Euryarchaeota also use the reductive acetyl-CoA pathway.
  • Some marine Crenarchaeota are capable of nitrification, suggesting these organisms may affect the oceanic nitrogen cycle, although these oceanic Crenarchaeota may also use other sources of energy.

• Cyanobacteria

  • Carbon dioxide is reduced to form carbohydrates via the Calvin cycle.

• Hydrogen Oxidation

  • In many organisms, a second cytoplasmic hydrogenase is used to generate reducing power in the form of NADH, which is subsequently used to fix carbon dioxide via the Calvin cycle.