The importance of oxygen in life

The importance of oxygen in life

Oxygen ( /ˈɒksɨdʒɨn/ ok-si-jin) is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς (oxys) ("acid", literally "sharp", referring to the sour taste of acids) and -γενής (-genēs) ("producer", literally "begetter"), because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a very pale blue, odorless, tasteless diatomic gas with the formula O₂.

                         Oxygen is a member of the chalcogen group on the periodic table and is a highly reactive nonmetallic element that readily forms compounds (notably oxides) with almost all other elements. Oxygen is a strong oxidizing agent and has the second highest electronegativity of all the elements (only fluorine has a higher electronegativity). By mass, oxygen is the third most abundant element in the universe after hydrogen and helium and the most abundant element by mass in the Earth's crust, making up almost half of the crust's mass. 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. Prior to 3.45 billion years ago, Earth's atmosphere and oceans were anoxic (i.e. without oxygen). This is supported by the existence of mass-independent fractionalization (MIF) of sulfur isotopes in sediments from this time period, for these can only form in the absence of oxygen . Then, between 2.45 and 1.85 billion years ago, molecular oxygen appeared, albeit at a small fraction of the current atmospheric level, due to the evolution   of photosynthetic cyanobacteria. Diatomic oxygen gas constitutes 20.8% of the volume of air.

                           Because it comprises most of the mass in water, oxygen comprises most of the mass of living organisms (for example, about two-thirds of the human body's mass). All major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone. Elemental oxygen is produced by cyanobacteria, algae and plants, and is used in cellular respiration for all complex life. Oxygen is toxic to obligately anaerobic organisms, which were the dominant form of early life on Earth until O₂ began to accumulate in the atmosphere. Another form (allotrope) of oxygen, ozone (O₃), helps protect the biosphere from ultraviolet radiation with the high-altitude ozone layer, but is a pollutant near the surface where it is a by-product of smog. At even higher low earth orbit altitudes atomic oxygen is a significant presence and a cause of erosion for spacecraft.

Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen (DO; molecular oxygen dissolved in the water) becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system. Dissolved oxygen is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity (both of which affect the solubility of oxygen in water). An aquatic system lacking dissolved oxygen (0% saturation) is termed anaerobic, reducing, or anoxic; a system with low concentration—in the range between 1 and 30% saturation—is called hypoxic or dysoxic. Most fish cannot live below 30% saturation. A "healthy" aquatic environment should seldom experience less than 80%. The exaerobic zone is found at the boundary of anoxic and hypoxic zones.

Oxygen depletion can result from a number of natural factors, but is most often a concern as a consequence of pollution and eutrophication in which plant nutrients enter a river, lake, or ocean, and phytoplankton blooms are encouraged. While phytoplankton, through photosynthesis, will raise DO saturation during daylight hours, the dense population of a bloom reduces DO saturation during the night by respiration. When phytoplankton cells die, they sink towards the bottom and are decomposed by bacteria, a process that further reduces DO in the water column. If oxygen depletion progresses to hypoxia, fish kills can occur and invertebrates like worms and clams on the bottom may be killed as well.

Oxygen saturation in the environment generally refers to the amount of oxygen dissolved in the soil or bodies of water. Environmental oxygenation can be important to the sustainability of a particular ecosystem. Insufficient oxygen (environmental hypoxia) may occur in bodies of water such as ponds and rivers, tending to suppress the presence of aerobic organisms such as fish. Deoxygenation increases the relative population of anaerobic organisms such as plants and some bacteria, resulting in fish kills and other adverse events. The net effect is to alter the balance of nature by increasing the concentration of anaerobic over aerobic species.

Eutrophication (Greek: eutrophia—healthy, adequate nutrition, development; German: Eutrophie) or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system. In other terms, it is the "bloom" or great increase of phytoplankton in a water body. Negative environmental effects include hypoxia, the depletion of oxygen in the water, which induces reductions in specific fish and other animal populations.

Oxygen saturation in the environment generally refers to the amount of oxygen dissolved in the soil or bodies of water. Environmental oxygenation can be important to the sustainability of a particular ecosystem. Insufficient oxygen (environmental hypoxia) may occur in bodies of water such as ponds and rivers, tending to suppress the presence of aerobic organisms such as fish. Deoxygenation increases the relative population of anaerobic organisms such as plants and some bacteria, resulting in fish kills and other adverse events. The net effect is to alter the balance of nature by increasing the concentration of anaerobic over aerobic species.

                       Most aquatic habitats are occupied by fish or other animals requiring certain minimum dissolved oxygen concentrations to survive. Dissolved oxygen concentrations may be measured directly in wastewater, but the amount of oxygen potentially required by other chemicals in the wastewater is termed an oxygen demand. Dissolved or suspended oxidizable organic material in wastewater will be used as a food source. Finely divided material is readily available to microorganisms whose populations will increase to digest the amount of food available. Digestion of this food requires oxygen, so the oxygen content of the water will ultimately be decreased by the amount required to digest the dissolved or suspended food. Oxygen concentrations may fall below the minimum required by aquatic animals if the rate of oxygen utilization exceeds replacement by atmospheric oxygen.

The reaction for biochemical oxidation may be written as:

Oxidizable material + bacteria + nutrient + O₂ → CO₂ + H₂O + oxidized inorganics such as NO₃ or SO₄

Oxygen consumption by reducing chemicals such as sulfides and nitrites is typified as follows:

S^-- + 2 O₂ → SO₄^--

NO₂^- + ½ O₂ → NO₃^-

Since all natural waterways contain bacteria and nutrient, almost any waste compounds introduced into such waterways will initiate biochemical reactions. Those biochemical reactions create what is measured in the laboratory as the biochemical oxygen demand (BOD).

Oxidizable chemicals (such as reducing chemicals) introduced into a natural water will similarly initiate chemical reactions . Those chemical reactions create what is measured in the laboratory as the chemical oxygen demand (COD).

Both the BOD and COD tests are a measure of the relative oxygen-depletion effect of a waste contaminant. Both have been widely adopted as a measure of pollution effect. The BOD test measures the oxygen demand of biodegradable pollutants whereas the COD test measures the oxygen demand of biogradable pollutants plus the oxygen demand of non-biodegradable oxidizable pollutants.

What do we breath?

The air we breathe is generally composed of 78% nitrogen and 20.8% oxygen by volume. The other gases together, called trace gases, comprise the remaining 1%. These are argon, carbon dioxide, neon, helium, methane, krypton, hydrogen and xenon. The level of impurities in the air varies with geographic locations or with proximity to industrial areas or highways carrying dense traffic.

Ever since the Industrial Revolution started in the second half of the 18th century, substituting human and animal labor for machine labor, the rate of combustion of fossil fuels has been increasing. To produce the energy needed to power this machines, fuels such as gasoline and oil must be burned. These combustion processes use up oxygen and produce carbon dioxide.

Combustion processes are therefore slowly reducing the concentration of oxygen in the air we breathe. This means we have to breath more air to get sufficient oxygen.

Importance of oxygen

Oxygen is absolutely essential to support the process of "vital combustion" which maintains human life. Although a person can live for weeks without food or for days without water, he or she dies in minutes if deprived of oxygen.

The human body must have oxygen to convert the carbohydrates, fats, and proteins in our diet into heat, energy, and life. This process is known as "metabolism".

Oxygen is the essential element in the respiratory processes of most of the living cells. One of the main applications of oxygen is medical and biological life support. An major oxygenation of the lungs contribute to the elimination of toxins. The more oxygen we have in our system, the more energy we produce.

There is no life without chemistry, but there is chemistry without life."

A living thing is more than a machine, more than a chemical laboratory.

Oxygen is what is known as a highly reducing gas: it likes to combine with other molecules like atmospheric gases or surface rocks. It is the second-most electronegative atom in the periodic table after flourine; this means that oxygen has a strong tendency to rip electrons from other atoms. As a consequence, any given oxygen molecule has a relatively short lifetime in the atmosphere. Before the rise of photosynthesis, a process which produces oxygen and continues to this day to replenish our supply, Earth's atmosphere had no appreciable quantity of oxygen whatsoever.

Photosynthesis works by combining CO2 and H2O with energy derived from light to form O2, an additional amount of H2O, and glucose (C6H12O6 ) which the plant may then use for energy. The photosynthetic equation may be written as:

6 CO 2 + 12 H 2O + photons → C 6H 12O 6 + 6 O 2 + 6 H 2O

OXYGEN benefits the human body by:
The human body is about two-thirds oxygen, Oxygen's influence and its role in Human Body

In the human body, the oxygen is absorbed by the blood stream in the lungs, being then transported to the cells where an elaborated change process takes place.

Oxygen plays a vital role in the breathing processes and in the metabolism of the living organisms.

Probably, the only living cells that do not need oxygen are some anaerobic bacteria that obtain energy from other metabolic processes. The nutrient compounds, inside of the cell, are oxidized through complex enzymatic processes. This oxidation is the source of energy of most of the animals, mainly of mammals. The products are carbon dioxide and water (exhaled air has a relative humidity of 100%), which are eliminated by the human body through the lungs.

1. HEIGHTENS CONCENTRATION, ALERTNESS AND MEMORY. 90% OF OUR ENERGY COMES FROM OXYGEN, AND ONLY 10% FROM FOOD AND WATER
2. OXYGEN IS VITAL TO YOUR IMMUNE SYSTEM, MEMORY, THINKING AND SIGHT PROMOTES HEALING AND COUNTERS AGING.
3. STRENGTHENS YOUR HEART, REDUCING THE RISK OF HEART ATTACKS
4. CALMS YOUR MIND AND STABILIZES YOUR NERVOUS SYSTEM
5. SPEEDS UP THE BODY'S RECOVERY AFTER PHYSICAL EXERTION
6. PROVIDES A NATURAL REMEDY FOR HEADACHES, MIGRAINES AND   HANGOVERS
7.RELIEVES TEMPORARY ALTITUDE DISCOMFORT
8. MPROVES MUSCLE STIFFNESS, SUPPORTS PRE-ATHLETIC PERFORMANCE
9. LESSENS CHRONIC FATIGUE SYNDROME AND GIVES YOU BETTER SLEEP PATTERNS
              Understanding how oxygen works inside the human body is important. The air we breathe in is separated inside our lungs. The 2 hydrogen atoms separate from the 1 oxygen atom and the oxygen reverts back to its gaseous state.
             This gaseous oxygen then enters the blood stream and makes a 20- minute trip around the entire body where the red blood cells drop off oxygen where it is needed and pick up waste and refuse to be delivered to their respective waste disposal ports.
             The human body does all of this on its own with no conscious help from us. Our only job is to make sure that we are getting enough gaseous oxygen into our bloodstream.
The physiology of respiration in human

In human physiology, respiration is the transport of oxygen from the clean air to the tissue cells and the transport of carbon dioxide in the opposite direction. This is only part of the processes of delivering oxygen to where it is needed in the human body and removing carbon dioxide waste.

Not all of the oxygen breathed in is replaced by carbon dioxide; around 15% to 18% of what we breathe out is still oxygen. The exact amount of exhaled oxygen and carbon dioxide varies according to the fitness, energy expenditure and diet of that particular person.

Air-breathing of humans, respiration of oxygen includes four stages:

• Ventilation from the ambient air into the alveoli of the lung.
• Pulmonary gas exchange from the alveoli into the pulmonary capillaries.
• Gas transport from the pulmonary capillaries through the circulation to the peripheral capillaries in the organs.
• Peripheral gas exchange from the tissue capillaries into the cells and mitochondria.

Note that ventilation and gas transport require energy to power mechanical pumps (the diaphragm and heart respectively), in contrast to the passive diffusion taking place in the gas exchange steps.

Nasal breathing of respiration process refers to the state of inhaling and exhaling through the nose.

It is considered superior to mouth breathing for several reasons. Breathing through the nose has numerous health benefits due to the fact that the air travels to and from the external environment and the lungs through the sinuses as opposed to the mouth. The sinuses do a better job of filtering the air as it enters the lungs.

In addition, the smaller diameter of the sinuses creates pressure in the lungs during exhalation, allowing the lungs to have more time to extract oxygen from them. When there is proper oxygen-carbon dioxide exchange, the blood will maintain a balanced pH. If carbon dioxide is lost too quickly, as in mouth breathing, oxygen absorption is decreased.

Nasal breathing is especially important in certain situations such as dehydration, cold weather, laryngitis, and when the throat is sore or dry because it does not dry the throat as much.

Nasal breathing in public is considered to be more socially acceptable and attractive than mouth breathing.

The major function of the respiratory process is gas exchange. As gas exchange occurs, the acid-base balance of the body is maintained as part of homeostasis. If proper ventilation is not maintained two opposing conditions could occur: 1) respiratory acidosis, a life threatening condition, and 2) respiratory alkalosis.

The Lungs are the human organs of respiration.

Human body have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately 1500 miles (2,400 km) of airways and 300 to 500 million alveoli, having a total surface area of about 75 m2 in adults — roughly the same area as a tennis court. Furthermore, if all of the capillaries that surround the alveoli were unwound and laid end to end, they would extend for about 620 miles.

The lung capacity depends on the person's age, height, weight, sex, and normally ranges between 4,000 and 6,000 cm3 (4 to 6 L).

For example, females tend to have a 20–25% lower capacity than males. Tall people tend to have a larger total lung capacity than shorter people. Smokers have a lower capacity than non-smokers. Lung capacity is also affected by altitude.

People who are born and live at sea level will have a smaller lung capacity than people who spend their lives at a high altitude. This is because the atmosphere is less dense at higher altitude, and therefore, the same volume of air contains fewer molecules of all gases, including oxygen. In response to higher altitude, the body's diffusing respiration capacity increases in order to be able to process more air.

When someone living at or near sea level travels to locations at high altitudes (eg. the Andes, Denver, Colorado, Tibet, the Himalayas, etc.) s/he can develop a condition called altitude sickness because their lungs cannot respirate sufficiently in the thinner air.

Human lungs are to a certain extent 'overbuilt' and have a tremendous reserve volume as compared to the oxygen exchange requirements when at rest. This is the reason that individuals can smoke for years without having a noticeable decrease in lung function while still or moving slowly; in situations like these only a small portion of the lungs are actually perfused with blood for gas exchange.

As oxygen requirements increase due to exercise, a greater volume of the lungs is perfused, allowing the body to reach its CO2/O2 exchange respiration requirements.
Chemical composition of the human body

The size of the human body is firstly determined by diet and secondly by genes. Body type (slim, fat, tall, petite, wide-shouldered, etc) and body composition (percentages of fat, bone and muscle) are influenced by postnatal factors such as diet and exercise.

By the time the human reaches adult-hood, the body consists of close to 100 trillion cells. Each is part of an organ system designed to perform essential life functions.

By mass, human cells consist of 65-90% water (H2O), and a significant portion is composed of carbon-containing organic molecules. Oxygen therefore contributes a majority of a human body's mass, followed by carbon.

99% of the mass of the human body is made up of the six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus.

In order to understand the relation of food to the sustenance and repairing of the body, it will be necessary to learn, first, of what the human body is composed, and the corresponding elements contained in the food required to build and keep the body in a healthy condition.

The following table gives the approximate analysis of a man weighing 148 pounds: Element	Percent by mass
Oxygen (O)	65
Carbon (C)	18
Hydrogen (H)	10
Nitrogen (N)	3
Calcium (Ca)	1.5
Phosphorus (P)	1.2
Potassium (K)	0.2
Sulfur (S)	0.2
Chlorine (Cl)	0.2
Sodium (Na)	0.1
Magnesium (Mg)	0.05
Iron (Fe), Cobalt (Co), Zinc (Zn), Iodine (I)	<0.05 each
Selenium (Se), Fluorine (F)	<0.05 each

As food contains all these elements, and as there is constant wearing and repair going on in the body, it will be readily seen how necessary some knowledge of the relation of food to the body is, in order to preserve health.

Oxygen is found in almost all biomolecules that are important to (or generated by) life. Only a few common complex biomolecules, such as squalene and the carotenes, contain no oxygen. Of the organic compounds with biological relevance, carbohydrates contain the largest proportion by mass of oxygen.

All fats, fatty acids, amino acids, and proteins contain oxygen (due to the presence of carbonyl groups in these acids and their ester residues).

"The molecules of hydrogen, oxygen, carbon, nitrogen, iron, phosphorus, calcium, and so on, in a living body, are themselves no more alive than the same molecules in inorganic matter. Nearly nine tenths of a living body is water;

Chemistry is all-potent. A mechanical mixture of two or more elements is a simple affair, but a chemical mixture introduces an element of magic.

Free or single atoms are very rare; they all quickly find their mates or partners. This eagerness of the elements to combine is one of the mysteries.

Life comes to matter as the flowers come in the spring, — when the time is ripe for it, — and it disappears when the time is over-ripe.

The air may disappear, the water may disappear, combustion may cease; but oxygen, hydrogen, nitrogen, and carbon will continue somewhere.