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Biomolecules in Living Organisms

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Biomolecules in Living Organisms: An Introduction

Biomolecules are the larger molecules required for life that are created from tiny organic molecules. When united, they comprise the bulk of a cell's mass. In addition to carbon as an organic molecule, biomolecules include hydrogen, oxygen, nitrogen, phosphorus, sulphur, and other trace elements. Biomolecules, including carbohydrates, proteins, lipids, etc., are produced by the body and necessary for all biological processes. They tend to show variance in terms of nature, kind, structure and physical characteristics.

Biomolecules are chemical substances created by living things that range in size from small molecules (metabolites) to huge molecules (protein and carbs). The right quantities of biomolecules are essential for the proper operation of live cells since biomolecules serve as the fundamental building blocks of living creatures; their modification may result in cellular dysfunction. Therefore, it is essential to have a precise biomolecule composition to maintain the health of the cells and living organisms.

What are Biomolecules?

Any organic molecule found in a live cell, like carbohydrates, proteins, lipids, etc., is referred to as a biomolecule, that contributes to the metabolic and harmonized functions of living things. Chemical evolution gave rise to the earliest biomolecules with a size range from tiny macromolecules like nucleic acids, carbohydrates, etc. to huge macromolecules like hormones, metabolites, etc.

The following are some properties of biomolecules:

  • Majority of them are asymmetric organic molecules.

  • They possess particular dimensions and shapes.

  • Their chemical properties are determined by the functional group.

  • Macromolecules are made up of simpler molecules called building blocks.

Types of Biomolecules

There are 4 biomolecule types, namely:


Carbohydrates, also called polysaccharides, are macromolecules. They are monosaccharide monomers–based polymers (sugar molecules). Simple carbohydrates are monosaccharides (example- glucose), whereas lengthy sugar chains are polysaccharides (example- cellulose and starch). The majority of living cells have abundant carbohydrate levels in their final metabolic by-products.


Polymers having monomeric units of 20 amino acids constitute the proteins, of which 9 are essential and 11 are non-essential. Long polypeptide chains are created when amino acids are joined by peptide bonds in a particular order. A central C is linked to an amino group, a carboxylic group, hydrogen, and several R groups form amino acids, which substitute methane.


Fats, oils, steroids, and other hydrophobic macromolecules are considered lipids. The most basic lipids are fatty acids that are made of carboxylic acids with long-chain variable R groups, either as saturated or unsaturated. Trihydroxy propane is created when fatty acids combine with glycerol to generate triglycerides. The primary components of the cell membrane are phospholipids, with a phosphate group as a hydrophilic head and two hydrophobic fatty acid tails.

Nucleic Acids

All living things have nucleic acids, polymers of nucleotides, as their genetic material. Every nucleotide has a nitrogenous base (pyrimidines and purines), sugar, and a terminal phosphate group. A nucleoside is a basis connected to sugar (deoxyribose in DNA and ribose in RNA), which combines with a phosphate group to generate nucleotides.

Biomolecules Classification

Classification of Carbohydrates

Based on the chemical structure and polymerization, carbohydrates are divided into simple and complex groups.

Simple Carbohydrates

Simple carbohydrates include one or two sugar molecules and are commonly accessible in dairy products, fruits, sweets, etc. They are:

1. Monosaccharides

A monosaccharide of carbohydrates includes glucose, galactose, mannose, etc. Monosaccharides are arranged structurally as follows:

2. Disaccharides

A disaccharide is created when two monosaccharides are joined. Disaccharides include sucrose, lactose, maltose, etc.

3. Oligosaccharides

Oligosaccharides are the carbohydrate molecules created by the fusion of 2–9 monomers. Trioses, pentoses, and hexoses are the kinds of oligosaccharides.

Complex Carbohydrates


Complex carbohydrates, known as polysaccharides, contain two or more sugar units, which are produced when a high number of monomers are polymerized. Starch, glycogen, cellulose, etc. that contain just glucose molecules are examples of polysaccharides.

Classification of Proteins

Fibrous proteins and globular proteins are the two different forms of protein molecules. Fibrous proteins are stretched and insoluble, while globule proteins are soluble and compact. Primary, secondary, tertiary, and quaternary structures are a few of the protein structure types that can be found in fibrous and globular proteins.

Classification of Lipids

There are two major categories of lipids:

  • Non-Saponifiable Lipids - These cannot be hydrolysed into smaller molecules. Example: prostaglandins, cholesterol, etc.

  • Saponifiable Lipids - These can be hydrolysed due to the presence of one or more ester groups. Example: phospholipids and triglycerides.

Classification of Nucleic Acids

The two main forms of nucleic acids involved in the heredity and transmission of particular traits are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Pentose sugar, Phosphoric acid, and a few nitrogen-containing cyclic bases, like adenine (A), guanine (G), cytosine (C), and thymine (T), make up the double-strand helical structure of DNA. The double helix structure of RNA typically contains a single strand. Three different RNA types, messenger RNA (m-RNA), ribosomal RNA (r-RNA), and transfer RNA (t-RNA), have a particular function.

Importance of Biomolecules

The importance of biomolecules is described in the table below:




Important energy source for any physical functions of the body.


Important from the viewpoint of health and aid in tissue and cell production.


Extremely important both in terms of energy sources and human nutrition.

Nucleic Acids

Highly important because RNA aids in the body's protein synthesis, and DNA transmits the genetic information.

Clinical Significance

Numerous processes depend on biomolecules, including the storage of energy (carbohydrates), biochemical responses (hormones), and the preservation or transmission of genetic information (RNA/DNA). An insufficient intake of amino acids and carbohydrates can cause a variety of disorders; therefore, they are regarded as important.

Interesting Fact

It's interesting to note that in comparison to other elements, "carbon" serves as a "foundation element" for the critical function of biomolecules. Hence, the concentration of particular bio-molecules plays a key role in the well-being of living organisms.

Important Questions

1. What function do biomolecules play in living things?

Ans: The chemical compounds in living things for growth and development are called biomolecules. They are crucial for the survival of live cells.

2. What make up the inheritance units in living things?

Ans: The hereditary characteristic genes found in the chromosomes of cellular nuclei are the units of inheritance in living organisms.

Key Features

  • Biomolecules come in a variety of shapes and sizes by serving many different purposes.

  • Four main categories of biomolecules are proteins, lipids, nucleic acids, and carbohydrates, which are important for providing energy and structural stability.

  • Proteins carry out a variety of cellular functions, while nucleic acids (DNA and RNA) are the genetic building blocks made of nucleotides.

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FAQs on Biomolecules in Living Organisms

1. Do living organisms contain biomolecules?

Yes. Biomolecules are present in living organisms as chemical substances.

2. Which biomolecule contains genetic data?

Deoxyribonucleic acid, also known as DNA, is the molecule that carries the genetic material necessary for an organism's growth and functioning.

3. Water: A Biomolecule or not?

In Biology, water is not a passive solvent; rather, it actively participates in several biomolecular and cellular processes. It could be thought of as a distinct type of biomolecule that changes its shape and dynamics to accept different cell solutes and biological macromolecules.