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

Merriam-Webster dictionary defines molecular biology as:- "a branch of biology dealing with the ultimate physicochemical organization of living matter and especially with the molecular basis of inheritance and protein synthesis." Molecular biology involves the study of the structure and the functions of the cells & of the structures inside the cells(cell organelles, bio-molecular complexes, macro-molecules, enzymes), integrating them into the cores of Biochemistry and Genetics.

What does Molecular-level mean?

Molecular-level in terms of organizational level is distinguished purely by the size of the components. In terms of molecular biology, the molecular level denotes the series from the non-living biochemicals as found in the DNA/RNA to the macromolecules and the Cell Organelles. The molecular particles close to the organelle's sizes appear relatively significant and can be observed by advanced electron microscopy.

Hierarchical Presentation of the Organizational levels of living beings
Hierarchical Presentation of the Organizational levels of living beings

What does a Molecular biologist do?

Molecular biologists correspond to other scientists but work with the constituents of nature which can barely be observed, even with a microscope. They rely on radioactivity, isotopic reading, biochemical, and optical measurements, and various other techniques, to look into the diminutive nature of cellular constituents. Well-equipped laboratories with advanced technologies are assembled to conduct experiments.

The steps which molecular biologists follow can be broken down further into:

  • Understanding the cell and its components:

The cell is the most complex biological unit. Molecular biologists invest a bulk fraction of time in gaining information about the prominent structures of the cell (Nucleus, Mitochondria, Endoplasmic Reticulum(ER), Lysosomes, Ribosomes, Golgi complex, Vacuoles, etc.). The individual components inside the cells also called the cell organelles or the Biomolecular complexes, are outlined mainly by - whether they are membrane-bounded/non-bounded, with/without DNA, or both.

Almost all aspects of life are engineered at the molecular level, and without understanding molecules we can only have a very sketchy understanding of life itself. — Francis Crick / What Mad Pursuit: A Personal View of Scientific Discovery (1988)

Nature is believed to assign each of the cell components to a specific function, but not all of them have yet been discovered. Biologists review past findings and studies on the particulars, observe and analyze them in their experiments and try to uncover their roles in the cell.

Discovering these biological laws and a definite function for a specific group of macromolecules present in the cell helps to understand how the different parts of the cells function as a single entity despite being structurally and biochemically non-identical. Furthermore, it aids in accessing information about the dependency of the cell organelles on one another to perform various cellular processes.

Molecular Biology

Plunging deeper into the genetic level, biologists deal with DNA, RNA, proteins, enzymes, and other macromolecular structures. They observe the precise patterns of the DNA sequences and assign them as per specific character/function/protein coders in the genetic composition of the cells. Their study here also focuses on the genetic code transfer by the processes of transcription, translation, and replication of the fundamental genetic structures.

  • Replicate Biological Phenomena:

Molecular biologists establish the relationship between different components of the cell as biological theories or hypotheses. These hypotheses are tested by replicating the phenomenon of heterogeneous circumstances (environment, organisms, DNAs') for their validation and generalization.

Here, replicating essentially means conducting the original process in a test organism/substrate under similar biological conditions but in a different environment or host. Biologists utilize knowledge from biochemistry, microbiology, cell physiology, genetics, physics, and other sciences in the course. The cell organelles/genes/DNAs'/RNAs' are isolated, purified, and manipulated for the procedure, by a variety of scientific approaches, powerful laboratory equipment, and tested techniques. 

Molecular biology is essentially the practice of biochemistry without a license.— Erwin Chargaff/ Essays on Nucleic Acids (1963)

  • Conducting Research and other activities: 

It can be easily perceived that biologists conduct research, but it's merely understood what the research is based on. Research in scientific fields is pivotal for uncovering the secrets of nature - plants, organisms, bacteria, and all other organisms. Molecular biologists conduct intensive laboratory research for finding the ethos of life, for formulating scientific principles, and bring light, to their applications. These researches are the basis for professionals of the entire world like doctors, therapists, environmentalists, etc to depend on for new approaches and medicinal enhancements, which recently is being focused on stem cells, powerful antibiotics, and gene therapy for cancer treatment.

Molecular biologists also conduct academic activities, conferences, and seminars to give the general public an eye into the futuristic approaches to biology. Keeping informed the government and scientific sectors helps in gaining academic and monetary aid to keep continuing in the sphere of research. Also, they attract potential scientists in the mainstream of research and help in contrasting the complex molecular concepts to the ones who are already involved in related studies.

  • Generalize, Publish and apply findings:

Molecular biology illuminates the roots of life and shares its applications in all the worldly sciences. The depicted biological inferences when scientifically approved and endorsed for usage in living beings can be termed as generalized. The scientific findings are generally published as Research Papers, Journals in online databases by the biologists themselves. The applications of their inventive knowledge are deployed in an array of disciplines (Medicine, Agriculture, Biotechnology, Forensic science, Genetics, Environmental biology, etc.) for the enhancement of living beings and the scientific universe.