Important Elements for Life
Some elements are essential (some in large, some in small quantities) for
maintenance of our health, agriculture, and daily life use. We shall not attempt to cover all the elements known to be involved in the above-mentioned functions. Instead, we discuss only those presently recognized as most important or about which most is known. Based on one or both of these criteria, the functions of some elements are discussed.
(1) Iron
Iron is the second most abundant metal found in the earth's crust after aluminum. It has been known and used by humanity for a long time. Today, it is one of the best-known metals globally because of its very great economic and industrial importance. It is used for general engineering purposes such as corrugated sheets, car bodies, nails, screws, steel pipes, tools, etc.
Iron is essential to all living organisms. It is present at the active center of molecules.
(Hemoglobin and Myoglobin) responsible for oxygen carriers and of other types of molecules (cytochromes and Ferredoxins) for electron transport. Normally it is slightly toxic, but excessive intake can cause siderosis and damage to some organs.
The iron content in plant parts is generally between 50-250 ppm. It is absorbed, by
plant roots from the soil as Fe²⁺ and Fe³⁺ These irons are involved in photosynthesis.
(2) Sodium
It is used in sodium vapor lamps (which give a bright orange-yellow light) for street
lighting. Lt is used for the preparation of important compounds such as sodium peroxide (Na₂O₂). Sodium cyanide (NaCN) which is used in the extraction of gold. It is also used to prepare tetraethyl lead, which is added to petrol as an anti-knocking agent.
Sodium is a major component of vertebrate blood plasma. It is important in the different functions of living organisms. It is associated with some forms of hypertension in some individuals.
Plants absorb sodium as Na⁺¹, and its concentration varies widely from O.01 to
10% in leaf tissue. It is essential for halophytic plant species that accumulate salts in vacuoles to maintain turgor and growth. Crops that require sodium for optimum growth include spinach, Sugar beet, turnip, etc.
(3) Potassium
Potassium in the form of carbonates is used in the preparation of glass and soap. One of its other compounds, potassium phosphate, is used in the preparation of detergents. Potassium nitrate is used in the preparation of glass and explosive material. It plays an important role in nerve action and cardiac function. It is moderately toxic to mammals when injected intravenously otherwise harmless. Plant roots absorb potassium as K⁺. The potassium concentration in vegetative tissue usually ranges from 1 to 4% on a dry matter basis. Many plant enzymes require potassium for their activation.
(4) Magnesium
Because of its low density, Mg is used in preparing light but rough alloys such as
magnalium (a mixture of aluminum and magnesium). These alloys are used for the
construction of cars, aircraft, and moving parts of machines.
It is essential to all organisms. It is present in chlorophyll. It has electrochemical and
enzyme activating functions.
Magnesium is absorbed as Mg²⁺ , and its concentration in crops varies between 0.1 and 0.4%. The importance of Mg²⁺ is obvious since it is a primary constituent of the chlorophyll molecules, and without chlorophyll, the autotropic green plant would fail to carry on photosynthesis.
(5) Calcium
This element is used as a deoxidant in steel casting. It is used in the extraction of uranium and the preparation of calcium fluorides and calcium hydrides.
It is an essential element for all organisms; it is used in cell walls, bones, and some shells as important compound. It is involved in blood clotting.
In plants, calcium concentration ranges from 0.2 to 1%. Lt has an important role in
the structure and permeability of cell membranes. Lack of Ca²⁺ produces a general breakdown of membrane structures.
(6) Phosphorous
Phosphorous occurs in most plants in concentrations between 0.1 and 0.4%. Plants absorb either H2PO4− or HPO4− orthophosphate ions. The essential operation of elements in plants is in energy storage and transfer. Adenosine di and tri-phosphates (ADP and ATP) act as "energy currency" within the plants. In human beings, during carbohydrate metabolism and in plants during photosynthesis, the energy produced is stored in phosphate compounds,, i.e.,, ADP and ATP. When the phosphate compounds from either ATP or ADP is split off, a relatively large amount of energy (12,000) cal/mol) is liberated. This energy is used in growth and reproductive processes...
It is an important constituent of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), bones, teeth, some shells, membrane, phospholipids, Adenosine diphosphate (ADP),, and Adenosine triphosphate (ATP).
This element is used in the form of superphosphate and tri-phosphate in fertilizers. Phosphoric acid and its salts are used in the food industry, detergents,,, and baking powders. Phosphorous is also used in matches.
(7) Fluorine
Trace amounts of fluoride (2.5 ppm) in the diet is essential for optimal growth and
strengthens teeth in mammals.
Fluorine generally occurs in plant material in the range of 2-20 ppm in the dry matter,
although some plant species can accumulate much higher amounts. The high concentration of fluorine (i.e.,,, 200 ppm) in plants is toxic to animals. It is neither required for plant growth,, nor plays an essential role in plant metabolism.
Some fluorides and other compounds of fluorine are used as refrigerant, anesthetic, non-stick agent insulators. Sodium fluoride in trace amounts is used for the fluoridation of drinking water, while tin fluoride is used in many kinds of toothpaste to protect the decay of teeth.
(8) Chlorine
Although chlorine gas is very poisonous, it has many beneficial uses in daily life.
Lt is used to kill germs and bacteria and is commonly used in domestic bleaches. It is also used in water purification and swimming pools. Polyvinyl chloride is a common plastic compound of chlorine and is known as PVC. It has many uses, especially as an insulator or as a waterproofing material.
It is an essential element for higher plants and mammals. The sodium salt of chloride (NaC1) acts as an electrolyte and hydrochloric acid as digestive juices in the body. The deficiency of chloride causes the impaired growth in infants.
Chlorine is essential for higher plants. It is present in chloroplasts which is essential for photosynthesis. Plants that take up a large amount of C1-¹ usually have high water content.
(9) lodine
Lodine is used in making dyes for color photography and pharmaceutical chemicals. A dilute iodine solution in ethanol, known as a tincture of iodine, is commonly used as an antiseptic.
It is an essential element in many organisms. Low iodide availability in certain areas increases the incidence of goiter.
Lodine is not essential to plants but is reputed to produce stimulating effects on plant growth at low concentrations. In healthy plants, the iodine level is 0.5 ppm At higher concentrations.
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