Biomolecules: Chemical Composition Analysis

Table of Contents

Things around us have been classified as living and non-living things. All living organisms are made up of a fundamental unit called the cell. However, if we further divide a cell, we can see that it is made up of molecules which in turn are composed of atoms. The cell comprises inorganic and organic compounds. Thus, on the basis of the chemical analysis, we can conclude that everything in this world is made up of the same chemicals. They differ only in their proportion.

Let’s take a glance at biomolecules and its chemical composition in living organisms.

What is Biomolecule?

Biomolecules are all the carbon-containing compounds (organic compounds) present in the living entities. They are organic molecules present in living cells and are involved in the maintenance and metabolic processes of living organisms.

There are four major classes of Biomolecules –  

  1. Carbohydrates.
  2. Proteins.
  3. Nucleic acids.
  4. Lipids.

Every biomolecule is essential for body functions and is manufactured by the body. It can vary in nature, type, structure and functions. Biomolecules are made up of functional groups. Some of the Biomolecules are straight chains; others may be cyclic rings or both.  Moreover, they can vary in their physical properties such as water solubility and melting points.

In a living cell, the functional group of biomolecules is as follows:

Amino acids

Amino acids are carbon-containing compounds with a carboxylic acid group and the amino group found at the two ends. Each of these amino acids comprises one central carbon enclosed by four substituents. These substituents are a carboxylic acid group, amino group, hydrogen, and a variable group indicated by R. The variable group determines the type and nature of amino acid.

Also ReadAmino Acid


Lipids are a group of water-insoluble compounds that include fats, steroids, phospholipids and oils, etc. Depending upon constituents, lipids can be classified into different types. Fatty acids are simple lipids, composed of a variable group, R and a carboxyl group. These can either be unsaturated or saturated fatty acids. Glycerols are trihydroxy propane that combines with fatty acids to produce triglycerides. Several lipids comprise a phosphorus group having the organic chain and are known as phospholipids, which are the essentials of the plasma membrane.

Also Read: Lipids

Nucleic acids

Nucleic acids are the genetic materials present in an organism, which include DNA and RNA. They are polymeric molecules made of nucleotide monomers. They are the combination materials of nitrogenous bases, sugar molecules and phosphate groups linked by different bonds in a series of steps. Our body consists of heterocyclic compounds like pyrimidines and purines. These are nitrogenous compounds like adenine, guanine, cytosine, thymine and uracil. When these bases bond with ribose sugar, they form nucleosides. Nucleosides, in turn, bond with the phosphate group to give nucleotides like DNA and RNA.

Explore more about Difference Between DNA and RNA

Analysis of chemical composition

The elemental analysis of a cell shows that it is composed of various elements such as carbon, hydrogen, oxygen, sulphur, phosphorus, etc.

But what do these elements constitute? What are the properties of the compounds formed by these elements?

Only a chemical analysis can answer these questions.

Analytical techniques provide information regarding different compounds (organic and inorganic), their molecular formula and structures. They also help us to isolate and purify one compound from another.

Here is a simple experiment to find the Chemical Composition Analysis in Biomolecules.

Take a piece of living tissue and crush and mix it with an acid. After its filtration, we obtain two portions. The fraction which is obtained as filtrate is an acid-soluble portion while the other fraction is acid-insoluble, which retain on the filter membrane. This shows that within the tissues, there are two or more compounds that have distinct properties.

Take another piece of tissue and burn it. Once all the water in it is evaporated, all carbon compounds will be oxidized on burning. The left-out ash gives us the inorganic compounds like calcium, magnesium, sulfate, phosphate, etc., in the tissue.

Stay tuned with BYJU’S to learn more about biomolecules and their functions.

Frequently Asked Questions on Biomolecules


What are biomolecules?

The organic compounds that make up the cells in living things are known as biomolecules.


What are the classes of biomolecules?

The major classes of biomolecules are Carbohydrates, Proteins, Nucleic acids, and Lipids


What are the two fractions obtained from grounding the tissues?

The fractions obtained from grounding the tissues are acid-soluble fraction and acid-insoluble fraction.


What are the nucleotides made of?

Nucleotides are made of nucleoside and phosphate groups. Nitrogenous base and ribose sugar together constitute the nucleosides.


What are the four groups around the central carbon in the amino acid?

The four groups around the central carbon in the amino acid are the carboxylic acid group, amino group, hydrogen, and a variable group indicated by R.

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