What is Molecular Biology?

Molecular biology is the study of biology at a molecular level.

The field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry.
Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interrelationship of DNA, RNA and protein synthesis and learning how these interactions are regulated.

What is molecular biology?

Molecular biology is the branch of biology that studies the molecular basis of biological activity.

Living things are made of chemicals just as non-living things are, so a molecular biologist studies how molecules interact with one another in living organisms to perform the functions of life.

Molecular biologists conduct experiments to investigate the structure, function, processing, regulation and evolution of biological molecules and their interactions
with one another — providing micro-level insights into how life works.

Although there are many kinds of molecules in every living thing, most molecular biologists focus on genes and proteins. Proteins perform a huge diversity of functions within living cells and genes contain the information required to make more proteins.

The Complex Relationship of Genes & Proteins

Genes are segments of information stored on gigantic nucleic acid molecules and proteins are molecules in their own right, making both of these substances (and the relationship between them), extraordinarily important to study.

Molecular biologists work to identify and understand the parts of biological pathways. Proteins can:

  • Regulate and impact each other
  • Respond to signals from genes
  • Respond to signals from outside a cell

The long chain of these interactions is what many molecular biologists seek to fully document. Every step in a functional pathway is something that a disease can disrupt or a drug can target.  Understanding the role of each such molecule is important for understanding more complex aspects of how organisms live and work.

Molecular biologists can also seek to understand ways the structure of a molecule, including details such as the location and shape of active sites on a protein, affect how a molecule functions. Collecting this information not only provides basic knowledge into how biology works, but helps inform the efforts of other scientists who seek to manipulate that biology. Those scientists include drug designers and genetic engineers.

The Differences in Molecular Biology, Biochemistry & Genetics

Molecular biology has much in common with two related sciences: biochemistry and genetics. The three sciences all concern themselves with details of how organisms work at the molecular level. However, each focuses on a different area and have different applications.


Biochemistry often devotes more of its attention to molecules other than proteins. It also focuses on nucleic acids and to chemical effects that happen when larger quantities of a substance are present, such as the effects of venoms. Additionally, biochemistry uses many methods based in organic chemistry research.


Genetics is focused specifically on heritable traits and how changes in the genetic code affect an organism. This focus on heritability means that genetics is often best studied at the population level, making it a much larger-scale sort of field than molecular biology.

Each of these three fields overlap and influence the others. Genetics, in particular, has shared much with molecular biology, particularly with regards to the role of RNA. RNA can both store information like DNA and perform active functions like a protein.

Molecular Biology Laboratory Methods

Molecular biology is perhaps most famous for its distinctive suite of laboratory methods. Molecular biologists make extensive use of:

  • Molecular cloning
  • Polymerase
  • Chain reaction
  • Gel electrophoresis
  • Blotting

These techniques facilitate collecting, isolating and quantifying molecules of interest.

Studying protein and nucleic acid structure benefits from a different set of techniques, such as X-ray crystallography. Many molecular biologists make extensive use of computer modeling in their work.  Modern techniques, particularly those developed for genetics, are also altering the course of molecular biology research.

Molecular biology is a large and growing field, whose importance has yet to be fully realized. Many more advances in medicine, ecology and other areas will come out of molecular biology research as this science continues to grow and advance.

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