aerobic

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Aerobic

Aerobic refers to oxygen as it concerns an organism. Specifically, an organism that is described as being aerobic (or an aerobe) means that the organism needs oxygen to live. Some microorganisms can live without oxygen; they are called anaerobic.

Aerobic also refers to the need for oxygen in the utilization of foods. Bacteria are not dependent on oxygen to use a food source for energy, but most other living organisms do need oxygen. Fats, proteins, and sugars in the diet of organisms are chemically broken down in the process of digestion to release energy to drive life activities. If oxygen is present, maximum energy is released from the food, and the process is referred to as aerobic respiration. The analogy of a bonfire with the energy metabolism of living organisms is appropriate up to the point that both processes require fuel and oxygen to produce energy and yield simpler compounds as a result of the oxidation process. There are, however, a number of important differences between the energy produced by the fire and the energy that comes from organism metabolism. The fire burns all at once and gives off large quantities of heat and light. Aerobic oxidation in an organism, on the other hand, proceeds in a series of small and controlled steps. Much of the energy released in each step is recaptured in the high-energy bonds of a chemical called adenosine triphosphate (ATP), a compound found in all cells, which serves as an energy storage site. Part of the energy released is given off as heat.

Energy metabolism begins with an anaerobic sequence known as glycolysis. Since the reactions of glycolysis do not require the presence of oxygen, it is termed the anaerobic pathway. This pathway does not produce very much energy for the body, but it establishes a base for further aerobic steps that do have a much higher yield of energy. It is believed that cancer cells do not have the necessary enzymes to utilize the aerobic pathway. Since these cells rely on glycolysis for their energy metabolism, they place a heavy burden on the rest of the body.

The aerobic pathway is also known as the Krebs citric acid cycle and the cytochrome chain. In these two steps the byproducts of the initial anaerobic glycolysis step are oxidized to produce carbon dioxide, water, and many energy-rich ATP molecules. All together, all these steps are referred to as cell respiration. Forty percent of the glucose burned in cell respiration provides the organism with energy to drive its activities, while 60% of the oxidized glucose is dissipated as heat. This ratio of heat and energy is about the same as a power plant that produces electricity from coal.

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Aerobic

Aerobic means that an organism needs oxygen to live. Some microorganisms can live without oxygen and they are called anaerobic. Bacteria are not dependent on oxygen to burn food for energy , but most other living organisms do need oxygen. Fats, proteins , and sugars in the diet of organisms are chemically broken down in the process of digestion to release energy to drive life activities. If oxygen is present, maximum energy is released from the food, and the process is referred to as aerobic respiration . The analogy of a bonfire with the energy metabolism of living organisms is appropriate up to the point that both processes require fuel and oxygen to produce energy and yield simpler compounds as a result of the oxidation process. There are, however, a number of important differences between the energy produced by the fire and the energy that comes from organism metabolism. The fire burns all at once and gives off large quantities of heat and light . Aerobic oxidation in an organism, on the other hand, proceeds in a series of small and controlled steps. Much of the energy released in each step is recaptured in the high-energy bonds of a chemical called adenosine triphosphate (ATP), a compound found in all cells and serving as an energy storage site. Part of the energy released is given off as heat.

Energy metabolism begins with an anaerobic sequence known as glycolysis . Since the reactions of glycolysis do not require the presence of oxygen, it is termed the anaerobic pathway. This pathway does not produce very much energy for the body, but it establishes a base for further aerobic steps that do have a much higher yield of energy. It is believed that cancer cells do not have the necessary enzymes to utilize the aerobic pathway. Since these cells rely on glycolysis for their energy metabolism, they place a heavy burden on the rest of the body.

The aerobic pathway is also known as the Krebs citric acid cycle and the cytochrome chain. In these two steps the by-products of the initial anaerobic glycolysis step are oxidized to produce carbon dioxide , water , and many energy-rich ATP molecules. All together, all these steps are referred to as cell respiration. Forty percent of the glucose "burned" in cell respiration provides the organism with energy to drive its activities, while 60% of the oxidized glucose is dissipated as heat. This ratio of heat and energy is about the same as a power plant that produces electricity from coal .

See also Adenosine diphosphate; Krebs cycle.

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aer·o·bic / əˈrōbik; e(ə)ˈrō-/ • adj. Biol. relating to, involving, or requiring free oxygen: simple aerobic bacteria. ∎  relating to or denoting exercise that improves or is intended to improve the efficiency of the body's cardiovascular system in absorbing and transporting oxygen. DERIVATIVES: aer·o·bi·cal·ly adv.

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aerobic
1. Aerobic micro‐organisms (aerobes) are those that require oxygen for growth; obligate aerobes cannot survive in the absence of oxygen. The opposite are anaerobic organisms, which do not require oxygen for growth; obligate anaerobes cannot survive in the presence of oxygen.

2. Aerobic exercise is physical activity which requires an increase in heart rate and respiration to meet the increased demand of muscle for oxygen, as contrasted with maximum exertion or sprinting, when muscle can metabolize anaerobically, producing lactic acid, which is metabolized later, creating a need for increased respiration after the exercise has ceased (so‐called oxygen debt).

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aerobic Connected with, or dependent on, the presence of free oxygen or air.

An aerobic organism (aerobe), which includes animals and plants, can only survive in the presence of oxygen and depends on it for breaking down glucose into carbon dioxide and water to release energy. This process is called aerobic respiration. It differs from anaerobic respiration, in which an organism releases energy in the absence of oxygen.

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aerobic as applied to metabolism in cells of the body, or in microorganisms, means oxygen-utilizing. Aerobic metabolism occurs in most animal cells, and depends upon the presence of mitochondria, in which the key chemical processes take place. Aerobic bacteria inhabit the body surface and orifices — they do not have mitochondria. Aerobic exercise is that which is sustainable in balance with oxygen intake — for example, a 10 km race, or any milder rhythmic exercise.

Neil C. Spurway


See metabolism.
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Aerobic

Refers to either an environment that contains molecular oxygen gas (O2); an organism or tissue that requires oxygen for its metabolism ; or a chemical or biological process that requires oxygen. Aerobic organisms use molecular oxygen in respiration , releasing carbon dioxide (CO2) in return. These organisms include mammals, fish, birds, and green plants, as well as many of the lower life forms such as fungi , algae, and sundry bacteria and actinomycetes. Many, but not all, organic decomposition processes are aerobic; a lack of oxygen greatly slows these processes.

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aerobic
1. Of an environment: one in which air (oxygen) is present. In the case of a depositional environment, one with more than 1 ml of dissolved oxygen per litre of water. Compare ANAEROBIC; and DYSAEROBIC.

2. Of an organism: one requiring the presence of oxygen for growth, i.e. an aerobe.

3. Of a process: one that occurs only in the presence of oxygen.

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aerobic
1. Of an environment: one in which oxygen is present.

2. Of an organism: one requiring the presence of oxygen for its existence, i.e. an aerobe.

3. Of a process: one that occurs only in the presence of oxygen.