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BIOMOLECULES
Introduction
Every cell is composed of a variety of molecules and molecular aggregates. Thus, the molecules found in the cells of
organism are called biomolecules or biological molecules.
The science which deals with the study of molecules (chemicals) of the living organisms and the chemical changes
occurring in them is called biochemistry.
Chemical elements of life or biological elements –
1. The chemical elements are substances which can’t be broken up by ordinary chemical processes into simpler
substances.
2. The elements found in living matters are also found in non-living world.
3. Out of the 90 elements that compose air, water, rock, soil, only about 25 elements compose the living bodies.
4. These elements are compatible with life because of their special properties and they are therefore called as
biological elements or bio-elements.
5. The elements that constitute the living body are O, C, H, N, Ca, P, Cl, S, Na, K, Mg, I, Fe, Cu, Co, Zn, Si, Mn
Vanadium (V), Molybdenum (Mo), Boron (B), Chromium, (Cr), Tin (Sn), Al
Of these H, C, O, N, S, Na, Ca, Mg, Si are considered as essential elements found in living as well as
Earth’s crust.
Compounds of life (Biological compounds) –
1. The elements of life are rarely found as such in the cells. They generally occur as compounds an ion.
2. A compound is a substance composed of atoms of two or more different elements in specific proportion and with
a specific pattern of bonds. Eg. H2O molecule formed of O and H atoms is a compound.
3. An ion is an atom that carries a charge due to loss or gain of electron.
Kinds of compound –
Living organisms are composed of organic as well as inorganic compounds.
1. Inorganic compounds : They usually lack the element ‘C’. They have relatively small molecules with simple
structure and lower molecular weights. They are readily soluble in water and diffusible. They include water,
minerals, salts and ions and gases.
2. Organic compounds : They contain the element ‘C’. The ‘C’ atoms are bonded to form a chain or ring which serves
as a skeletal for organic molecules.
They have large molecules with complex structure and high molecular weight. They are insoluble or
slightly soluble and non-diffusible. They include carbohydrates, lipids, proteins, nucleotides.
Cellular Pool –
The aggregation of various kinds of biomolecules (organic and inorganic) found in a cell is referred to as the cellular pool.
The cellular pool has two phases – aqueous and non-aqueous.
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The inorganic molecules generally occur in the aqueous phase. Eg. Water is the most important which is about the
total mass of 70% - 90%.
The organic molecules occur in both aqueous and non-aqueous phase. Eg. Carbohydrate, Lipid, Amino acid, Protein
etc.
The chemicals of the cellular pool function as raw materials for carrying out various biochemical reactions of the
cell organelles and the cell.
Micromolecules and Macromolecules –
Depending upon their molecular weight and solubility, the compounds fall in two categories – micromolecules and
macromolecules
Micromolecules –
They are small in size and have low molecular weight, simple structure and often high solubility.
They are found in acid soluble pool.
These include inorganic compounds such as water, mineral salts and gases as well as organic compounds such as
sugar, lipids, amino acids and nucleotides.
The micromolecules are the substrates and products of metabolism in the cell.
They act as building blocks for the macromolecules.
They are formed of basic molecules like C, O, H and N.
Macromolecules –
They are large in size and have high molecular weights, complex molecular structure.
They occur in colloidal state being acid insoluble in the intracellular fluid.
They include only organic compounds, i.e., polysaccharides, proteins and nucleic acids.
They are formed by polymerization of large number of micromolecules.
Difference between micromolecules and macromolecules
Micromolecules Macromolecules
1 Are small in size Are large in size
2 Have low molecular weight Have high molecular weight
3 Have simple structure Have complex structure
4 Occur as molecular solution in the intracellular fluid Occur as colloidal solution in the intracellular fluid.
Form building blocks (monomers) of macromolecules Formed by polymerization of micromolecules
5 Eg. Inorganic compounds (H2O, salts, gases) as well as
organic compounds (sugars, lipids, amino acids, Eg. Only organic compounds (proteins, polysaccha
nucleotides). nucleic acids)
Nature of bonds which link monomers in a polymer
There are 3 different bonds which occur in the formation of polymeric biomolecules – peptide bond, glycosidic bond
and phosphodiester bond
1. Peptide bonds –
They are also called amide bonds.
BIOMOLECULES
Introduction
Every cell is composed of a variety of molecules and molecular aggregates. Thus, the molecules found in the cells of
organism are called biomolecules or biological molecules.
The science which deals with the study of molecules (chemicals) of the living organisms and the chemical changes
occurring in them is called biochemistry.
Chemical elements of life or biological elements –
1. The chemical elements are substances which can’t be broken up by ordinary chemical processes into simpler
substances.
2. The elements found in living matters are also found in non-living world.
3. Out of the 90 elements that compose air, water, rock, soil, only about 25 elements compose the living bodies.
4. These elements are compatible with life because of their special properties and they are therefore called as
biological elements or bio-elements.
5. The elements that constitute the living body are O, C, H, N, Ca, P, Cl, S, Na, K, Mg, I, Fe, Cu, Co, Zn, Si, Mn
Vanadium (V), Molybdenum (Mo), Boron (B), Chromium, (Cr), Tin (Sn), Al
Of these H, C, O, N, S, Na, Ca, Mg, Si are considered as essential elements found in living as well as
Earth’s crust.
Compounds of life (Biological compounds) –
1. The elements of life are rarely found as such in the cells. They generally occur as compounds an ion.
2. A compound is a substance composed of atoms of two or more different elements in specific proportion and with
a specific pattern of bonds. Eg. H2O molecule formed of O and H atoms is a compound.
3. An ion is an atom that carries a charge due to loss or gain of electron.
Kinds of compound –
Living organisms are composed of organic as well as inorganic compounds.
1. Inorganic compounds : They usually lack the element ‘C’. They have relatively small molecules with simple
structure and lower molecular weights. They are readily soluble in water and diffusible. They include water,
minerals, salts and ions and gases.
2. Organic compounds : They contain the element ‘C’. The ‘C’ atoms are bonded to form a chain or ring which serves
as a skeletal for organic molecules.
They have large molecules with complex structure and high molecular weight. They are insoluble or
slightly soluble and non-diffusible. They include carbohydrates, lipids, proteins, nucleotides.
Cellular Pool –
The aggregation of various kinds of biomolecules (organic and inorganic) found in a cell is referred to as the cellular pool.
The cellular pool has two phases – aqueous and non-aqueous.
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The inorganic molecules generally occur in the aqueous phase. Eg. Water is the most important which is about the
total mass of 70% - 90%.
The organic molecules occur in both aqueous and non-aqueous phase. Eg. Carbohydrate, Lipid, Amino acid, Protein
etc.
The chemicals of the cellular pool function as raw materials for carrying out various biochemical reactions of the
cell organelles and the cell.
Micromolecules and Macromolecules –
Depending upon their molecular weight and solubility, the compounds fall in two categories – micromolecules and
macromolecules
Micromolecules –
They are small in size and have low molecular weight, simple structure and often high solubility.
They are found in acid soluble pool.
These include inorganic compounds such as water, mineral salts and gases as well as organic compounds such as
sugar, lipids, amino acids and nucleotides.
The micromolecules are the substrates and products of metabolism in the cell.
They act as building blocks for the macromolecules.
They are formed of basic molecules like C, O, H and N.
Macromolecules –
They are large in size and have high molecular weights, complex molecular structure.
They occur in colloidal state being acid insoluble in the intracellular fluid.
They include only organic compounds, i.e., polysaccharides, proteins and nucleic acids.
They are formed by polymerization of large number of micromolecules.
Difference between micromolecules and macromolecules
Micromolecules Macromolecules
1 Are small in size Are large in size
2 Have low molecular weight Have high molecular weight
3 Have simple structure Have complex structure
4 Occur as molecular solution in the intracellular fluid Occur as colloidal solution in the intracellular fluid.
Form building blocks (monomers) of macromolecules Formed by polymerization of micromolecules
5 Eg. Inorganic compounds (H2O, salts, gases) as well as
organic compounds (sugars, lipids, amino acids, Eg. Only organic compounds (proteins, polysaccha
nucleotides). nucleic acids)
Nature of bonds which link monomers in a polymer
There are 3 different bonds which occur in the formation of polymeric biomolecules – peptide bond, glycosidic bond
and phosphodiester bond
1. Peptide bonds –
They are also called amide bonds.
