oxygen

Examples of oxygen in the following topics:

• Transport of Oxygen in the Blood

  • Although oxygen dissolves in blood, only a small amount of oxygen is transported this way.
  • The binding of oxygen to hemoglobin can be plotted as a function of the partial pressure of oxygen in the blood (x-axis) versus the relative Hb-oxygen saturation (y-axis).
  • The oxygen-carrying capacity of hemoglobin determines how much oxygen is carried in the blood.
  • The oxygen dissociates from the Hb molecule, shifting the oxygen dissociation curve to the right.
  • The oxygen dissociation curve demonstrates that as the partial pressure of oxygen increases, more oxygen binds hemoglobin.

• 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.

• Uses of Oxygen

  • Oxygen is essential for all aerobic organisms; common medical uses include oxygen therapy, hyperbaric medicine, and space suits.
  • Reactive oxygen species, such as superoxide ion (O2−) and hydrogen peroxide (H2O2), are dangerous by-products of oxygen use in organisms.
  • One of the medical uses of oxygen is oxygen therapy.
  • Oxygen tents were once commonly used in oxygen supplementation, but have since been replaced mostly by the use of oxygen masks or nasal cannulas.
  • Sudden cabin pressure loss activates chemical oxygen generators above each seat, causing oxygen masks to drop.

• Properties of Oxygen

  • Oxygen is an important part of the atmosphere and is necessary to sustain terrestrial life.
  • Oxygen is toxic to obligate anaerobic organisms (organisms which need a lack of oxygen for survival), which were the dominant form of early life on Earth, until O2 began to accumulate in the atmosphere.
  • Free oxygen is too chemically reactive to appear on Earth without the photosynthetic action of living organisms, which use the energy of sunlight to produce elemental oxygen from water.
  • Diatomic oxygen gas currently constitutes 20.8 percent of the volume of air.
  • The two oxygen atoms in diatomic oxygen are chemically bonded to each other with a spin triplet electron configuration.

• 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.

• Skin, Gills, and Tracheal Systems

  • Organisms that live in water also need a way to obtain oxygen.
  • Oxygen dissolves in water, but at a lower concentration in comparison to the atmosphere, which has roughly 21 percent oxygen.
  • The circulatory system can then carry the oxygenated blood to the other parts of the body.
  • The concentration of oxygen molecules in water is higher than the concentration of oxygen molecules in gills.
  • As water flows over the gills, oxygen is transferred to blood via the veins.

• Scuba Diving, the Bends, and Hyperbaric Oxygenation

  • Hyperbaric medicine, also known as hyperbaric oxygen therapy, is the medical use of oxygen at a level higher than atmospheric pressure.
  • Hyperbaric medicine, also known as hyperbaric oxygen therapy (HBOT), is the medical use of oxygen at a level higher than atmospheric pressure.
  • Under normal atmospheric pressure, oxygen transport is limited by the oxygen binding capacity of hemoglobin in red blood cells and very little oxygen is transported by blood plasma.
  • The high concentrations of oxygen in the tissues are beneficial in keeping oxygen-starved tissues alive, and have the effect of removing the nitrogen from the bubble, making it smaller until it consists only of oxygen, which is re-absorbed into the body.
  • Treatment is by hyperbaric oxygen therapy in a recompression chamber.

• Oxygen Transport

  • Hemoglobin is the primary transporter of oxygen with an oxygen binding capacity between 1.36 and 1.37 ml O2 per gram Hgb.
  • The function of Hgb is to provide a binding site for oxygen to carry oxygen throughout the bloodstream to the  systemic tissues for cellular respiration.
  • Higher PaO2 means higher saturation of oxygen in blood.
  • Carbon monoxide binds to hemoglobin in place of oxygen, so that less oxygen reaches the tissues, and can be fatal if severe enough.
  • The oxygen–hemoglobin dissociation curve plots the percent hemoglobin saturation (y-axis) against the partial pressure of oxygen in the blood (PO2).