oxygenic

Examples of oxygenic in the following topics:

• Oxygen

  • Obligate aerobes require oxygen for aerobic cellular respiration.
  • Facultative anaerobes can use oxygen, but also have anaerobic (i.e. not requiring oxygen) methods of energy production.
  • And finally, facultative anaerobes, which can grow without oxygen but can utilize oxygen if it is present.
  • Hydrogen then reacts with oxygen gas on a palladium catalyst to produce more water, thereby removing oxygen gas.
  • They require oxygen, but at a lower concentration. 5) Aerotolerant bacteria are not affected at all by oxygen, and they are evenly spread along the test tube.

• Oxygenic Photosynthesis

  • Oxygenic photosynthesis, provides energy to organism and allows for carbon fixation, all the while producing oxygen as a byproduct.
  • In plants, algae and cyanobacteria, photosynthesis releases oxygen .
  • This is called oxygenic photosynthesis.
  • In plants, algae and cyanobacteria, photosynthesis releases oxygen.
  • This is called oxygenic photosynthesis.

• Anaerobiosis and N2 Fixation

  • This slime layer acts as a barrier for oxygen.
  • In plants infected with Rhizobium, (legumes such as alfalfa or soybeans), the presence of oxygen in the root nodules would reduce the activity of the oxygen-sensitive nitrogenase.
  • Leghemoglobin is a nitrogen or oxygen carrier; naturally occurring oxygen and nitrogen interact similarly with this protein.
  • This allows an oxygen concentration that is low enough to allow nitrogenase to function but not so high as to bind all the O2 in the bacteria, providing the bacteria with oxygen for respiration.
  • Leghemoglobin, the protein which binds to oxygen, allowing nitrogenases to function in an oxygen free environment.

• Gas Requirements

  • Cells are grown and maintained at an appropriate temperature and gas mixture of oxygen, carbon dioxide, and nitrogen in a cell incubator.
  • Some example free-living diazotrophs include: 1) obligate anaerobes that cannot tolerate oxygen even if they are not fixing nitrogen.
  • They live in habitats low in oxygen, such as soils and decaying vegetable matter. 2) Facultative anaerobes that can grow either with or without oxygen, but they only fix nitrogen anaerobically.
  • Often, they respire oxygen as rapidly as it is supplied, keeping the amount of free oxygen low. 3) Aerobes that require oxygen to grow, yet their nitrogenase is still debilitated if exposed to oxygen. 4) Oxygenic photosynthetic bacteria generate oxygen as a by-product of photosynthesis, yet some are able to fix nitrogen as well. 5) And finally, Anoxygenic photosynthetic bacteria that do not generate oxygen during photosynthesis as they have only a single photosystem which cannot split water.
  • Cells are grown and maintained at an appropriate temperature and gas mixture of oxygen, carbon dioxide, and nitrogen in a cell incubator.

• Microbial Growth Cycle

  • Different kinds of bacteria need different amounts of oxygen to survive, which determines which bacteria can infect which parts of the body.
  • They are not able infect the skin because oxygen is present, and they can only grow in the presence of oxygen.
  • Conversely, obligate anaerobes are killed by oxygen and carry out fermentation.
  • Tetanus is an obligate anaerobe so it will infect areas where oxygen in limited.
  • Aerotolerant anaerobes breath anaerobically (without oxygen), but they are able to survive when oxygen is present.

• Fermentation Without Substrate-Level Phosphorylation

  • Even in the presence of abundant oxygen, yeast cells greatly prefer fermentation to oxidative phosphorylation, as long as sugars are readily available for consumption (a phenomenon known as the Crabtree effect).
  • In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen, via an electron transport chain.
  • For example, even in the presence of abundant oxygen, yeast cells greatly prefer fermentation to oxidative phosphorylation, as long as sugars are readily available for consumption (a phenomenon known as the Crabtree effect).
  • Fermentation occurs in mammalian muscle during periods of intense exercise where oxygen supply becomes limited, resulting in the creation of lactic acid.
  • Pyruvic acid supplies energy to living cells through the citric acid cycle (also known as the Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactic acid when oxygen is lacking (fermentation).

• Sources of Essential Nutrients

  • The sources of common essential nutrients are carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.
  • Carbon, nitrogen, phosphorus, sulfur, hydrogen, and oxygen are all examples of essential nutrients.
  • Some examples of these essential nutrients are carbon, oxygen, hydrogen, phosphorus, and sulfur.
  • The sources of common essential nutrients are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
  • Oxygen is an important component of both organic and inorganic compounds.

• Electron Donors and Acceptors in Anaerobic Respiration

  • In anaerobic respiration, a molecule other than oxygen is used as the terminal electron acceptor in the electron transport chain.
  • Anaerobic respiration is the formation of ATP without oxygen.
  • This method still incorporates the respiratory electron transport chain, but without using oxygen as the terminal electron acceptor .
  • Nitrate, like oxygen, has a high reduction potential.
  • A molecule other than oxygen is used as the terminal electron acceptor in anaerobic respiration.

• Nitrate Reduction and Denitrification

  • Denitrification is a widely used process; many facultative anaerobes use denitrification because nitrate, like oxygen, has a high reduction potential
  • In general, it occurs where oxygen is depleted and bacteria respire nitrate as a substitute terminal electron acceptor.
  • Due to the high concentration of oxygen in our atmosphere, denitrification only takes place in anaerobic environments where oxygen consumption exceeds the oxygen supply and where sufficient quantities of nitrate are present.
  • When faced with a shortage of oxygen, some rhizobia species are able to switch from O2-respiration to using nitrates to support respiration.
  • Generally, denitrification takes place in environments depleted of oxygen.

• Anoxygenic Photosynthesis

  • Photosynthetic reactions can be anoxygenic, thus they do not produce oxygen.
  • Chlorophototrophy can further be divided into oxygenic photosynthesis and anoxygenic phototrophy.
  • Oxygenic and anoxygenic photosynthesizing organisms undergo different reactions either in the presence of light or with no direct contribution of light to the chemical reaction (colloquially called "light reactions" and "dark reactions", respectively).
  • Anoxygenic photosynthesis is the phototrophic process where light energy is captured and converted to ATP, without the production of oxygen.
  • Bacteriochlorophylls c-g have the corresponding "peak" absorbance at more blue wavelengths when dissolved in an organic solvent, but are similarly red-shifted within their natural environment (with the exception of bacteriochlorophyll f, which has not been naturally observed).Unlike oxygenic phototrophs, anoxygenic photosynthesis only functions using (by phylum) either one of two possible types of photosystem.