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Biological Molecules III

May 29, 2013

Biological Molecules  III (chem)

The chemicals like oxygen, hydrogen, nitrogen and carbon are present in elements and the presence of these chemicals is in similar proportion. It should be kept in mind that at the molecular level, the chemical analysis consists of few types of compounds. When a molecule is sourced or originated by a living body is called Biological Molecule.

These molecules form organ’s backbone. The nature of these compounds is basically organic.  Some Examples of Biological Molecules are proteins, nucleic acids, lipids. Small molecules like natural products; primary and secondary metabolites are also some examples.

A biogenic substance is another name for Biological Molecules. Organic chemistry is the chemistry of compounds that has carbon. This branch is called organic because it was believed that living organisms only possesses such compounds.  This belief was soon withdrawn when an organic compound was manufactured from an inorganic one in the laboratory.

Nowadays innumerable organic compounds are manufactured in the laboratory. Six protons and six electrons can be found in a carbon atom.  Two of them can be found in the inner shell while four are present in the outer shell. 4 Major Biological Molecules are carbohydrates, lipids, proteins, and nucleic acids. Four Major Biological Molecules are also known as macromolecules. Compounds that are made of carbon, hydrogen and oxygen are called carbohydrates.

Monosaccharides are one of the common forms of carbohydrates. The summary formula of monosaccharides is CH2O. 3 to 7 carbon atoms can be found in monosaccharides.  Glyceraldehyde is the simplest form of sugar. Monosaccharides contain comparatively small molecules. Glucose is a monosaccharide sugar and thus they play a very important role in our life. A ketone group or an aldehyde group can be found in their structure.

The functional group of this molecule is two types, one is –OH and another one is –CHO.

Disaccharides are nothing but two monosaccharide sugars forming a bond with absence of water in it. Huge numbers of monosaccharides give rise to polysaccharides and they are bonded by glycosidic bonds. In case of plants, Starch is an example of polysaccharide while for animals glycogen can be cited as an example.  Out of the 4 Main Biological Molecules, lipid is an important molecule because it is considered as the building block of all membranes.

They also help to store energy which is also known as triglycerides. Polar or hydrophilic heads can be found in lipids. They also have one to three tails which are non polar or hydrophobic. So they are also known as amphiphilic.

They are also known by the name fats and oils.  Like carbohydrates, lipids also contain carbon, hydrogen and oxygen but it contains oxygen in very small amount. The chemical characteristics of lipids are they are not soluble in water and depending on their structure; they can be solid or liquid at room temperature. Proteins are not same as carbohydrates or lipids. An amino group is present in proteins which has nitrogen in it.  They are formed from chains of amino acids which are very long and most of them have very large molecules.  Examples of nucleic acids are DNA or RNA. They are formed from nucleotides.


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