Elemental composition of living matter
All living matters are made up of many chemical compounds
Compounds form by the combination of many elements
Thus living organisms have chemical nature
Among the Ninety two naturally occurring elements about 20 – 25% of elements which constitute the living matter and are essential to continue healthy life and reproduce are called Essential elements (In human 25 & in plants 17)
C, H, N, O, P, S, K, Mg, Ca, Na, Cl, B, Mn, Zn, Cu, Mo, Si, V, I, Cr, Co (general)
Out of them Oxygen (O), Carbon (C), Hydrogen (H) and Nitrogen (N) make up 96% of living matter
Calcium (Ca), Phosphorus (P), Potassium (K) and Sulphur make up most of the remaining 4% of the mass of the organism
Based on the natural abundance of the essential elements in the living matter, can be divided into two
Macro Elements
Essential elements required by an organism in relatively high amount and found 0.01% or more in dry weight
Have low molecular weight (40)
Found in all elements C, H, N, O, P, S, K, Mg, Ca – 9
In addition to above some organisms (human) have Na, Cl, Fe
| Element | % in animal (human) | % in plant (Corn) | Function | |
| 01 | Oxygen | 65% | 44.4% | Major component of organic molecules |
| 02 | Carbon | 18.5% | 44% | Major component of organic molecules |
| 03 | Hydrogen | 9.5% | 6.24% | Major component of organic molecules |
| Component of amino acids | ||||
| Component of proteins | ||||
| Component of nucleotides | ||||
| Component of nucleic acids | ||||
| Component of coenzymes | ||||
| Component of enzymes | ||||
| Component of Chlorophyll | ||||
| 05 | Phosphorus | 1% | 0.2% | Component of ADP and ATP |
| Component of nucleic acids | ||||
| Component of phospholipids | ||||
| Component of several coenzymes | ||||
| 06 | Sulphur | 0.3% | 0.17% | Components of some amino acids and
proteins |
| Component of coenzyme – A | ||||
| 07 | Potassium | 0.4% | 0.92% | Protein synthesis |
| Operation of stomata | ||||
| 08 | Calcium | 1.5% | 0.23% | Component of cell walls |
| Maintenance of membrane structure and permeability | ||||
| Activates some enzymes. | ||||
| 09 | Magnesium | 0.1% | 0.18% | Component of chlorophyll molecule |
| Activates many enzymes |
Trace Elements
Essential elements required by an organism in minute quantities and found less than 0.01% in dry weight
B, Co, Cu, Cr, F, I, Fe, Mo, Mn, Se, Si, Sn, V, Zn
Some elements such as Iron (Fe) are required by all organisms while some are required only by certain species of animals (Iodine – Vertebrates)
| Element | Function |
| Sodium | · Osmosis |
| · Ionic balance | |
| · Nervous impulse transmission | |
| · Extracellular fluid | |
| Chlorine | · Extracellular fluid |
| · Enzyme activator | |
| · Osmosis | |
| · Ionic balance | |
| Iron | · Chlorophyll synthesis |
| · Component of cytochromes. | |
| · Component of nitrogenase | |
| · Component of blood pigments | |
| · Enzyme activator | |
| Manganese | · Activator of certain enzymes |
| Zinc | · Activator of many enzymes |
| · Activate formation of Chlorophyll | |
| Boron | · Carbohydrate transport |
| · Nucleic acid synthesis. | |
| Copper | · Activator or component of certain enzymes |
| Molybdenum | · Nitrogen fixation |
| · Nitrate reduction |
Elements in human body
Element Carbon
All living substances are made up of carbon
Because;
