Atrace element is achemical element of a minute quantity, a trace amount, especially used in referring to amicronutrient,[1][2] but is also used to refer to minor elements in the composition of arock, or otherchemical substance.
Innutrition, trace elements are classified into two groups: essential trace elements, and non-essential trace elements. Essential trace elements are needed for many physiological and biochemical processes in both plants and animals. Not only do trace elements play a role in biological processes but they also serve as catalysts to engage inredox – oxidation and reduction mechanisms.[3] Trace elements of someheavy metals have abiological role as essentialmicronutrients.
The two types of trace element inbiochemistry are classed as essential or non-essential.
An essential trace element is adietary element, amineral that is only needed in minute quantities for the proper growth, development, and physiology of the organism.[4] The essential trace elements are those that are required to perform vital metabolic activities in organisms.[5] Essential trace elements inhuman nutrition, and other animals includeiron (Fe) (hemoglobin),copper (Cu) (respiratory pigments),cobalt (Co) (Vitamin B12),iodine (I),manganese (Mn),chlorine (Cl),molybdenum (Mo),selenium (Se) andzinc (Zn) (enzymes).[5][6] Although they are essential, they become toxic at high concentrations.[7]
Non-essential trace elements includesilver (Ag),cadmium (Cd),mercury (Hg), andlead (Pb). They have no known biological function in mammals, with toxic effects even at low concentration.[5]
The structural components of cells and tissues that are required in the diet in gram quantities daily are known asbulk elements.[8]
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