Molecular Biology in Medicine: From Genes to Therapeutics

Dedicated to the advancement of human health through molecular insight and scientific compassion.

Abstract: Molecular biology has transformed modern medicine by uncovering the molecular basis of life, disease, and therapeutics. Through technologies such as DNA sequencing, polymerase chain reaction (PCR), gene therapy, and CRISPR gene editing, molecular biology now plays a central role in diagnostics, personalized medicine, cancer treatment, infectious disease management, and regenerative medicine. This article examines the major applications of molecular biology in medicine, supported by real-world examples and scientific references.

Introduction

Molecular biology is the branch of science that investigates the structure and function of biological molecules, particularly DNA, RNA, and proteins, which are the foundation of life. Its emergence in the mid-20th century, following the discovery of the DNA double helix structure by James Watson and Francis Crick in 1953, revolutionized biology and medicine. What began as a discipline focused on genes and protein synthesis has grown into a powerful force driving medical breakthroughs.

Today, molecular biology enables physicians and scientists to understand diseases not merely at the level of tissues and organs, but at their most fundamental cause – abnormalities at the molecular and genetic levels. This shift from symptom-based medicine to molecular medicine has allowed early diagnosis, targeted treatment, and even the correction of defective genes responsible for inherited disorders.

The integration of molecular biology into clinical practice has given rise to new medical fields, including molecular diagnostics, gene therapy, and precision medicine. From cancer research to infectious disease control and drug development, molecular biology has transformed the landscape of healthcare. The following sections explore the major applications of molecular biology in medicine and how they contribute to improving human health.

1. Molecular Diagnostics: Transforming Disease Detection

Molecular diagnostics is one of the most impactful applications of molecular biology in medicine. Unlike traditional diagnostic methods that rely on symptoms, imaging, or biochemical assays, molecular diagnostics detects disease at the genetic and molecular levels, often before symptoms appear. This enables early intervention, improves treatment outcomes, and reduces mortality rates.

Molecular diagnostics relies heavily on the detection and analysis of nucleic acids (DNA or RNA) associated with specific diseases. By identifying genetic variations, mutations, or pathogen-specific gene sequences, clinicians can diagnose diseases with high sensitivity and specificity.

1.1 Polymerase Chain Reaction (PCR) in Diagnostics

The polymerase chain reaction (PCR), developed by Kary Mullis in 1985, is a revolutionary technique that allows the amplification of specific DNA sequences. PCR makes it possible to detect even a single molecule of DNA in a sample by creating millions of copies of a targeted sequence. Real-time PCR (qPCR) has become a routine diagnostic tool in hospitals and laboratories.

Applications of PCR in Medicine:

Infectious disease detection: PCR enables rapid identification of pathogens such as Mycobacterium tuberculosis, HIV, Hepatitis B virus (HBV), and SARS-CoV-2. During the COVID-19 pandemic, RT-PCR (reverse transcription PCR) became the global gold standard for diagnosing SARS-CoV-2 infection by detecting viral RNA.

Cancer diagnostics: PCR is used to detect oncogenes (cancer-causing genes) and mutations in tumor suppressor genes such as TP53 and BRCA1/2, aiding in cancer classification and treatment planning.

Prenatal testing: PCR can detect genetic abnormalities such as cystic fibrosis, thalassemia, and Down syndrome from fetal DNA found in maternal blood.

PCR’s sensitivity, speed, and versatility make it a cornerstone of molecular medicine.

DNA Sequencing and Clinical Genomics

DNA sequencing allows scientists to determine the exact order of nucleotides in a DNA molecule. The Human Genome Project, completed in 2003, mapped the entire human genome and paved the way for genomic medicine. Next-generation sequencing (NGS) technologies now allow entire genomes to be sequenced within days at a fraction of the earlier cost.

Medical Applications of DNA Sequencing:

Diagnosis of rare genetic diseases: Many conditions caused by single-gene mutations (e.g., Duchenne muscular dystrophy, Huntington’s disease) are identified through whole-exome or whole-genome sequencing.

Cancer genome profiling: Sequencing tumor DNA helps identify driver mutations and select targeted therapies.

Pathogen surveillance: Genome sequencing is used in epidemiology to track disease outbreaks and antibiotic resistance.

NGS has transformed medical genetics and opened new possibilities in personalized medicine.

 Molecular Biomarkers

Biomarkers are measurable molecules that indicate normal or abnormal biological processes. Molecular biomarkers are now widely used in clinical decision-making.

Examples:

Prostate-specific antigen (PSA) for prostate cancer screening

HER2 gene amplification in breast cancer treatment selection

BCR-ABL fusion gene in chronic myeloid leukemia diagnosis

Molecular biomarkers improve diagnostic accuracy and allow prediction of disease progression and therapeutic response.

2. Molecular Biology in Oncology: Understanding and Treating Cancer

Cancer is fundamentally a genetic disease caused by mutations that disrupt normal cell growth and division. Molecular biology has uncovered the genetic basis of cancer and revolutionized oncology by enabling personalized treatment strategies.

2.1 Oncogenes and Tumor Suppressor Genes

Oncogenes are mutated genes that promote uncontrolled cell growth, while tumor suppressor genes prevent cell division or trigger cell death when necessary. Mutations in key regulatory genes lead to cancer development.

Examples include mutations in the KRAS oncogene found in colorectal and pancreatic cancers and the loss of function of tumor suppressor genes like TP53, commonly mutated across many cancer types. Understanding these mutations allows clinicians to classify cancers not only by tissue origin but also by molecular subtype, enabling personalized treatment strategies.

2.2 Targeted Cancer Therapies

Traditional cancer treatments such as chemotherapy and radiotherapy kill both cancerous and healthy cells, causing significant side effects. Molecular biology has advanced oncology by enabling targeted therapy, drugs designed to specifically attack cancer cells based on their genetic abnormalities.

Examples of Targeted Therapies:

Trastuzumab (Herceptin): Used to treat HER2-positive breast cancer by binding to the HER2 receptor and inhibiting tumor cell growth.

Imatinib (Gleevec): A tyrosine kinase inhibitor used to treat chronic myeloid leukemia (CML) by targeting the BCR-ABL fusion protein produced by a chromosomal translocation known as the Philadelphia chromosome.

Erlotinib and Gefitinib: Target EGFR mutations in non-small cell lung cancer.

These therapies exemplify precision oncology, where treatment is guided by individual tumor genetics rather than a one-size-fits-all approach.

2.3 Cancer Immunotherapy and Molecular Biology

Molecular biology has also led to major progress in cancer immunotherapy, treatments that harness the patient's immune system to fight cancer.

CAR-T Cell Therapy: Involves modifying a patient’s T cells to express chimeric antigen receptors (CARs) that recognize and destroy cancer cells. CAR-T therapy has shown remarkable success in treating blood cancers like acute lymphoblastic leukemia (ALL).

Immune Checkpoint Inhibitors: Drugs such as pembrolizumab (Keytruda) and nivolumab (Opdivo) block proteins like PD-1 and CTLA-4, which cancer cells exploit to evade immune detection.

Immunotherapy represents a major shift in oncology, from directly killing cancer cells to empowering the immune system to do so.

2.4 Liquid Biopsy

A recent breakthrough in molecular oncology is the liquid biopsy, a non-invasive blood test that detects fragments of tumor DNA (circulating tumor DNA or ctDNA). Liquid biopsies are used for:

Early cancer detection

Monitoring tumor evolution and treatment resistance

Detecting cancer recurrence

This technique provides a less invasive alternative to traditional surgery-based biopsies and allows real-time tracking of tumor genetics.

3. Gene Therapy: Correcting Genetic Diseases at the Source

Gene therapy involves altering the genetic material of a patient’s cells to treat or prevent disease. Molecular biology makes this possible by enabling identification of defective genes and developing methods to replace, repair, or silence them.

Gene therapy uses vectors, typically modified viruses such as adeno-associated viruses (AAVs) - to deliver therapeutic genes into patient cells.

3.1 Types of Gene Therapy

Gene addition: Introducing a functional copy of a defective gene (e.g., adding a healthy CFTR gene for cystic fibrosis research).

Gene silencing: Using RNA interference (RNAi) to silence harmful genes.

Gene correction: Fixing mutations directly using genome-editing tools.

3.2 Approved Gene Therapies

Several gene therapies have been approved and are now in clinical use:

Luxturna: Treats inherited retinal dystrophy caused by RPE65 gene mutations, restoring partial vision.

Zolgensma: A life-saving gene therapy for spinal muscular atrophy (SMA) that replaces the defective SMN1 gene in infants.

Strimvelis: Used to treat ADA-SCID, a severe combined immunodeficiency disorder.

These treatments demonstrate the power of molecular therapy to cure diseases once considered untreatable.

4. CRISPR-Cas9 and Gene Editing in Medicine

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and the associated Cas9 enzyme represent one of the most revolutionary breakthroughs in molecular biology. First adapted for gene editing in 2012 by Jennifer Doudna and Emmanuelle Charpentier, CRISPR-Cas9 allows scientists to edit DNA sequences with unprecedented precision.

4.1 How CRISPR Works

CRISPR functions like molecular scissors guided by RNA. A designed guide RNA (gRNA) directs the Cas9 enzyme to a specific DNA sequence, where it cuts the DNA strand. The cell then repairs into a new one  through gene editing

There are many other areas in medicine, too, where molecular biology is applied such as:

Stem Cells & Regenerative Molecular Medicine

Pharmacogenomics and Personalized Medicine

Molecular Biology in Infectious Disease Control

Molecular Biology in Vaccine Development (mRNA vaccines, etc.)

Molecular Imaging and Biomarker Research, and much more. However, we shall not go into them as they will run into hundreds of pages beyond the scope my short articles in this blog. 

Molecular Biology: The Language of Life and Its Transformative Power (Part 2)

Molecular Biology: The Language of Life and Its Transformative Power

 

by blogger lim ju boo (lin ru wu) 

 

Understanding Life from Molecules to Medicine

Molecular biology is the study of life at its most fundamental level, examining the structure, function, and interactions of biological molecules that form the basis of living organisms. It bridges the gap between genetics and biochemistry, and today it stands at the heart of modern biological and medical research.

From deciphering the structure of DNA in 1953 to designing lifesaving mRNA vaccines during the recent COVID-19 pandemic, molecular biology has revolutionized the way humanity understands and manipulates the processes of life.

1. Foundations of Molecular Biology

At its core, molecular biology investigates the behavior of macromolecules, especially nucleic acids (DNA and RNA) and proteins.

Nucleic Acids: DNA and RNA

DNA (deoxyribonucleic acid) stores genetic information in the form of genes. 

RNA (ribonucleic acid) acts as the messenger and interpreter of genetic information and plays roles in catalysis (ribozymes), regulation (miRNA), and protein synthesis.

Proteins

Proteins perform most cellular functions—from catalyzing reactions (enzymes) to transporting molecules, regulating gene expression, and defending against pathogens (antibodies).

2. The Central Dogma of Molecular Biology

Proposed by Francis Crick in 1958, the central dogma explains the directional flow of genetic information:

DNA  to RNA (translation)

RNA  to Protein (translation) 

Stage	Description
Replication	DNA makes exact copies of itself             during cell division.
Transcription	DNA is transcribed into messenger         RNA (mRNA).
Translation	Ribosomes read mRNA and assemble     amino acids into proteins.

3. Core Techniques in Molecular Biology

 

Modern molecular biology is driven by innovative laboratory techniques:

Technique	Purpose
PCR (Polymerase Chain Reaction)	Amplifies DNA for diagnostics and forensics.
Gel Electrophoresis	Separates DNA, RNA, or proteins by size.
DNA Cloning	Produces identical DNA copies using plasmids.
DNA Sequencing (NGS)	Reads nucleotide order, enables genome projects.
CRISPR-Cas9	Precise gene editing for correcting mutations.
Proteomics	Studies proteins with mass spectrometry.
Recombinant DNA Technology	Produces insulin, growth hormone, vaccines.

4. Molecular Biology and Related Fields

Molecular biology connects deeply with other branches of science:

Field	Relationship
Genetics	Studies heredity; molecular biology explains gene function.
Biochemistry	Studies chemical processes; molecular biology focuses on DNA, RNA, and proteins.
Cell Biology	Examines cellular function using molecular mechanisms.
Biotechnology	Applies molecular techniques for industry and medicine.

5. Applications of Molecular Biology

5.1 Medicine

1. Gene Therapy treats diseases like hemophilia by replacing faulty genes.

2. Cancer precision therapy targets tumor-specific mutations.

3. mRNA vaccines (Pfizer-BioNTech, Moderna) use genetic instructions to stimulate immunity.

4. Prenatal and carrier testing detect inherited disorders like thalassemia.

5.2 Agriculture

Development of drought-resistant crops (e.g. Bt corn).

5.3 Golden rice engineered to produce vitamin A.

Forensic Science 

DNA fingerprinting helps solve crimes and identify disaster victims. 

6. Evolutionary Biology

DNA comparison reveals evolutionary relationships among species.

Supports Darwin’s theory with molecular evidence.

7. Synthetic Biology

Scientists design artificial DNA circuits and even synthetic cells.

Genomics – study of entire genomes.

Transcriptomics – study of RNA expression patterns.

Proteomics and Metabolomics – understanding disease at system levels.

AI-driven molecular design – speed up drug discovery.

Ethical debates – over designer babies and gene editing.

Summary:

Molecular biology is not merely a discipline, it is a revolution that has changed science, medicine, and our understanding of life itself. By decoding the molecular language of DNA and proteins, humanity has gained the power not only to study life but to redesign it. With that power comes great responsibility, demanding ethics, wisdom, and compassion.

The Future of Molecular Biology

Molecular biology continues to evolve with big data and computational tools:

References

1. Watson, J. D., & Crick, F. H. C. (1953). Nature, 171(4356), 737–738.

2. Crick, F. (1958). Symposium of the Society for Experimental Biology, 12, 138–163.

3. Mullis, K. (1990). Nobel Lecture: The polymerase chain reaction.
Doudna, J. A., & Charpentier, E. (2014). Science, 346(6213), 1258096.

4. Alberts, B. et al. (2015). Molecular Biology of the Cell (6th ed.). Garland.

5. Lodish, H. et al. (2021). Molecular Cell Biology (9th ed.). W.H. Freeman.

6. National Human Genome Research Institute. Human Genome Project Timeline.

(We shall in the next two articles see how we can use molecular biology for the advancement of medicine, and how we can also use it in forensic science to detect and fight crimes using Malaysian murder cases as examples) 

Title: Molecular Biology: The Language of Life (An Introduction - Part 1)

 Molecular Biology: The Language of Life and Its Transformative Power Across Science,  Medicine to Forensic Investigations 

Dedicated to the pursuit of scientific truth and the beauty of life at the molecular level.

Molecular biology is one of the most dynamic and influential branches of modern science, shaping our understanding of life from the smallest molecular interactions to the complexity of organisms and ecosystems. Emerging in the mid-20th century from the fusion of genetics, biochemistry, and structural biology, molecular biology provided answers to questions that had puzzled scientists for centuries: How is hereditary information stored? How is it copied and passed from one generation to the next? How do cells know what to do, and how do they build themselves from simple chemical components? The birth of molecular biology transformed biology from a largely descriptive science into a mechanistic and predictive discipline based on universal molecular principles.

The history of molecular biology began with remarkable discoveries that illustrated the power of interdisciplinary thinking. In 1869, Swiss physician Friedrich Miescher isolated "nuclein" from white blood cells, unknowingly discovering DNA. Yet for decades, scientists believed that proteins were the carriers of genetic information due to their structural complexity. This assumption was overturned only in 1944 when Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrated that DNA, not protein, was the hereditary material in bacteria. This was soon followed by the Hershey-Chase experiment in 1952, which confirmed DNA's genetic role using viral infections of bacteria.

The true revolution began in 1953 when James Watson and Francis Crick, using X-ray crystallography data from Rosalind Franklin and Maurice Wilkins, proposed the now-famous double helix structure of DNA. This discovery revealed how DNA could both store information and replicate itself accurately, through complementary base pairing, laying the foundation for the new science of molecular biology. Just five years later, in 1958, Francis Crick proposed the "central dogma of molecular biology," which stated that genetic information flows from DNA to RNA to protein. Although later refined to accommodate discoveries like reverse transcription and RNA editing, the central dogma still provides a conceptual framework for understanding gene expression.

Since then, molecular biology has rapidly evolved, driving major scientific revolutions: recombinant DNA technology in the 1970s allowed genes to be cut and inserted into other organisms; PCR (polymerase chain reaction), developed by Kary Mullis in 1983, enabled the amplification of DNA; and in 2003 the Human Genome Project revealed the complete DNA sequence of humans. Today, technologies like CRISPR-Cas9 gene editing, epigenomics, and synthetic biology are ushering in a new era where we not only study life but can redesign it.

This article explores the foundations, mechanisms, tools, interdisciplinary scope, and profound applications of molecular biology in fields such as medicine, biotechnology, agriculture, forensic science, evolution, and environmental science. By tracing its development and examining its expanding applications, we will see how molecular biology has truly become the universal language of life.

Molecular biology rests upon an elegant yet powerful truth: all living organisms, from bacteria to humans, are built upon universal molecular principles. Despite the incredible diversity of life, the same four nitrogenous bases found in DNA - adenine, thymine, cytosine, and guanine - encode hereditary instructions in every known species. This astonishing conservation of molecular design unifies all organisms in a single biological continuum. In this way, molecular biology reveals a profound reality: life is both diverse and fundamentally unified at the molecular level.

At its foundation, molecular biology explores the molecular architecture and functions of cellular processes. It is concerned primarily with nucleic acids and proteins—molecules that store, transmit, and execute genetic information. DNA (deoxyribonucleic acid) serves as the long-term repository of genetic instructions required for the formation and maintenance of life, while RNA (ribonucleic acid) and proteins carry out the functional execution of those instructions. Together, they shape the biochemical identity of cells and enable growth, adaptation, and reproduction.

One of the most important conceptual breakthroughs in molecular biology was the discovery of the complementary nature of DNA strands, enabling faithful replication. During cell division, DNA unwinds, and each strand acts as a template for the synthesis of a new complementary strand. This precise and conservative mechanism ensures genetic continuity between generations of cells. DNA polymerase, the enzyme responsible for DNA replication, not only builds new strands but also performs proofreading, reducing replication errors and maintaining genomic stability.

From replication, molecular biology advances to the central dogma: the transfer of information from DNA to RNA to protein. This flow of information begins with transcription, a process in which RNA polymerase binds to DNA at specific promoter regions and synthesises a matching strand of messenger RNA (mRNA). This mRNA molecule, now carrying the genetic message, exits the nucleus (in eukaryotic cells) and travels to ribosomes, where translation occurs. Here, codons, three-nucleotide sequences on mRNA, are read sequentially to assemble amino acids into polypeptide chains. Transfer RNA (tRNA) plays a vital role in delivering the correct amino acids to the ribosome based on codon-anticodon pairing. As amino acids join through peptide bonds, the resulting polypeptide folds into a functional protein.

Proteins are the ultimate effectors of cellular behaviour. They act as enzymes regulating metabolic reactions, structural components that provide mechanical support, transport proteins that carry essential molecules, receptors that interpret signals from the environment, and antibodies that defend against pathogens. The relationship between protein structure and function is one of the core principles of molecular biology. Even minor genetic mutations that alter amino acid sequences can lead to significant structural changes in proteins, resulting in diseases such as sickle cell anaemia, cystic fibrosis, or certain forms of cancer.

Gene regulation is another essential theme in molecular biology. Cells do not express all of their genes at once; instead, gene expression is tightly controlled to ensure that the right proteins are produced in the right amounts at the right time. In prokaryotes, gene regulation is achieved through operon systems such as the lac operon in Escherichia coli, which controls lactose metabolism based on environmental conditions. In eukaryotes, regulation is more complex and involves epigenetic mechanisms, heritable modifications to DNA that influence gene activity without altering the DNA sequence itself. These include DNA methylation and histone modification, both of which control chromatin structure and accessibility. Epigenetics has reshaped our understanding of heredity, development, and disease susceptibility, demonstrating how environmental factors such as diet, stress, or toxins can influence gene expression across generations.

At the heart of every biological process lies molecular interaction. DNA interacts with proteins such as histones to form chromatin. RNA molecules interact with ribosomes to guide protein synthesis. Enzymes bind substrates with remarkable specificity, catalyzing reactions critical to metabolism. These interactions operate in precise networks, forming molecular pathways that sustain cellular life. Understanding these pathways has been vital in revealing the molecular basis of diseases and developing targeted therapeutic strategies.

The study of molecular biology was accelerated dramatically by advances in experimental techniques. The development of restriction enzymes in the 1970s allowed scientists to cut DNA at specific sequences, giving rise to recombinant DNA technology and the birth of genetic engineering. Restriction enzymes, along with DNA ligase and plasmid vectors, enabled scientists to insert genes into bacteria, plants, and animals, laying the groundwork for modern biotechnology. This innovation led to the production of human insulin using genetically modified bacteria, the first monumental achievement of pharmaceutical biotechnology.

The polymerase chain reaction (PCR), invented by Kary Mullis in 1983, revolutionized molecular biology by making it possible to amplify specific DNA sequences rapidly and precisely. PCR has become indispensable in diagnostics, evolutionary biology, archaeology, and forensic science. It enables the detection of pathogens, the analysis of ancient DNA samples, and the identification of individuals based on genetic profiles.

Following PCR, the sequencing of DNA marked another turning point in molecular biology. Frederick Sanger's chain termination method, developed in 1977, allowed scientists to determine the exact sequence of nucleotides in DNA. By 2003, this technology enabled the completion of the Human Genome Project, which revealed that humans possess approximately 20,000 protein-coding genes—far fewer than previously expected. The project opened new fields such as genomics and bioinformatics, shifting biology from gene-by-gene investigation to whole-genome analysis.

Modern molecular biology has entered the era of precision manipulation of genetic material. CRISPR-Cas9, a gene-editing technology adapted from bacterial immune defense systems, now allows scientists to cut and modify DNA with unprecedented precision and efficiency. This technology holds immense potential for correcting genetic disorders, improving crops, combating infectious diseases, and advancing synthetic biology. Gene drives, based on CRISPR, have even been explored to control mosquito populations and reduce the transmission of malaria.

In parallel, transcriptomics, proteomics, and metabolomics have emerged as powerful disciplines that study RNA transcripts, proteins, and metabolic pathways on a large scale. These 'omics' fields provide a comprehensive view of how genes, proteins, and metabolic reactions interact as systems.

What is life? By Mark Chit Tat

Below is a comment written by Mr Mark Chit Tat following my article on

 "What Is Life? A Dialogue Between Biology, Thermodynamics, and the Breath of God (Part 2)"

He posted his comment 30 mins ago  

But I thought I should make it a small article written by him instead of going into the comment column 

Here is what Mr Mark wrote:

No small dialogue, "a conversation still unfinished," Dr.Lin Ru Wu (林 如 武), your name also speaks aptly of the balance and elements of life. A dialogue of the weightier and "dense"🙂 issues of life, its meaning or purpose, something that is more than what we know or can understand.

After all, it had been "hidden" from us since that day the first Man chose not to eat of that Tree of Life but of the Tree of Knowledge of Good and Evil. So life is somewhat reduced to something like just birth and death, clueless of God's Plan A, so much so that Solomon, the wisest of the ancients lamented that "all is vanity"! But reiterated that "The end of the matter, everything having been heard, fear God and keep His commandments, for this is the entire man.(Eccles 12:8 &13, Rabbi A.J.Rosenberg, Chabad.org)".

However, all that you had shared earnestly and tirelessly in this blog of yours is so propitious to us all and shall remain a legacy accessible and beneficial to many in years to come too.

Jia you! 加油! Dr.Lin Ru Wu (林 如 武)

What Is Life? A Dialogue Between Biology, Thermodynamics, and the Breath of God (Part 2)

  

This is Part 2, a continuation of my thoughts in Part 1 - to give it a more philosophical touch on the definition of life in this link:  

https://scientificlogic.blogspot.com/2025/10/what-is-life-dialogue-between-biology.html

Life is the most familiar and yet the most mysterious phenomenon in the universe. Every second, countless living things awaken, feed, divide, heal, and die; still, the essence that makes them alive remains elusive. The cell biologist defines life in it by its metabolism and replication, the physicist by energy exchange and entropy, the philosopher by consciousness, and the theologian by the breath of God. Each perspective touches part of a greater truth, and together they form a dialogue between science and spirit, a conversation still unfinished.

Biology begins its answer with the cell, that shimmering unit of order in a sea of chaos. Within its fragile membrane, thousands of reactions proceed in exquisite coordination, examples,  proteins fold, DNA copies, ATP fuels every pulse of work. The biologist calls this self-sustaining network “autopoiesis”, the ability of matter to maintain and reproduce itself. Yet even as we map every gene and molecule, something greater seems to hover above the chemistry, like a melody arising from vibrating strings. A living system is not merely a collection of parts; it is dynamic wholeness sustained by information, pattern, and purpose.

Physiology extends the story into the rhythms of energy. Life feeds on disequilibrium. Every heartbeat, every neuron’s spark, depends on gradients, of ions, gases, and potentials. When these gradients flatten, life ceases. From the standpoint of thermodynamics, a living organism is a local rebellion against entropy, continuously importing free energy from its surroundings to keep its inner order intact. Schrödinger, pondering this paradox, wrote that organisms “feed on negative entropy.” We might say more simply that life borrows time from the universe’s long drift toward disorder.

Yet thermodynamics also humbles biology. No creature can outrun the second law forever. Cells age, tissues falter, and entropy reclaims what structure had defied it. Death, in this light, is not a punishment but a physical reconciliation - a return of organized energy to cosmic equilibrium. Still, even as matter decays, information can endure: in offspring, in memory, in the genome that whispers forward through time. Thus physics does not extinguish meaning; it transposes it into new forms.

Philosophy approaches from another side. The vitalists once argued that living beings possess a special essence, a “vital spark” beyond chemistry. Modern science dismissed that notion when it learned to synthesize organic compounds from inorganic ones, yet the intuition persists that something non-mechanical animates the living. Today, some philosophers of mind echo that intuition when they ask whether consciousness can emerge from matter alone. Is awareness merely an algorithm of neurons, or is it the universe becoming self-aware through us? Between mechanism and mystery lies the field where wonder still grows.

Across cultures, humanity has never been content with a purely mechanical account of life. Ancient Egyptians spoke of the ka, the life-force breathed into each person. In Hindu thought, prana is the cosmic breath that circulates through all beings. Chinese philosophy calls it qi, the flowing energy of heaven and earth. The Hebrew Scriptures describe creation with a similar image: “The LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul” (Genesis 2:7). In this simple verse, dust and breath meet, the physical and the divine entwined.

The biological breath and the biblical breath, though different in language, describe the same marvel: that matter can host awareness, desire, and compassion. Oxygen enters the lungs, diffuses into blood, fuels the mitochondria that power thought and love. But breath is more than gas exchange; it is the symbol of participation, the rhythmic reminder that life is shared. Each inhalation draws in the world; each exhalation returns a part of ourselves. When the final breath leaves, the body remains, but the pattern - the harmony of exchanges- is gone.

From a thermodynamic viewpoint, this cessation is simply the collapse of gradients; from a spiritual viewpoint, it is the release of spirit. Both can be true within their frames. The scientist observes the dispersal of energy; the believer perceives a passage. Between them stands the mystery that language can barely hold.

If we compare definitions, science emphasizes organization, metabolism, growth, adaptation, and reproduction. Theology speaks of soul, purpose, and divine image. Yet neither definition alone suffices. An artificial cell might one day mimic every metabolic step, but would it feel alive? A theologian might affirm that all breath comes from God, but must also acknowledge the physical processes that sustain it. The two accounts do not cancel each other; they complete one another like stereo channels revealing depth.

Death, therefore, is not the antithesis of life but part of its continuity. The atoms that once formed a heartbeat soon nourish soil, plankton, or star-dust anew. Energy changes costume but not existence. As Ecclesiastes reminds us, “Then shall the dust return to the earth as it was: and the spirit shall return unto God who gave it” (Ecclesiastes 12:7). Even in decay, life’s story expands.

Culturally, people have translated this intuition into rituals and ethics. Funerary rites, from the pyramids to modern memorials, affirm that life’s essence deserves reverence. Philosophers from Aristotle to Bergson spoke of entelechy or élan vital, a striving toward fulfillment that shapes every organism. In modern biology, this striving becomes the language of homeostasis and feedback loops, systems perpetually adjusting to preserve integrity. Whether we call it purpose or regulation, the tendency is the same: life seeks to remain itself.

The dialogue between biology and theology grows most intimate when we ask not what life is, but why it is. Evolution explains the mechanisms of adaptation, yet it cannot alone address why the universe gives rise to beings capable of asking questions. Physics can chart the energy exchanges of a heartbeat, yet it cannot explain why music can quicken it. Meaning itself seems to bloom in the interstices between data and devotion.

In recent decades, the science of complexity has offered a bridge. From chaos theory to systems biology, we learn that self-organization can arise spontaneously from simple rules, that feedback can produce order from noise. But even this elegant mathematics evokes wonder: why should the laws of nature permit such harmony at all? The more we decode the machinery of life, the more its existence feels like a gift rather than an accident.

Perhaps that is why poets and prophets speak of life as light. “In Him was life; and the life was the light of men” (John 1:4). Light and life are both acts of transformation, energy becoming visibility, matter becoming awareness. Thermodynamics tells us that every photon absorbed by a leaf becomes sugar, and every sugar molecule can become thought. Scripture tells us that divine light enlightens every human being. The metaphors converge: to live is to shine.

From a public-health perspective, recognizing this unity carries practical wisdom. To care for life is to respect its delicate balance of energy and purpose - nutrition, rest, love, and community all sustain the thermodynamic miracle within us. Pollution, exploitation, and neglect are not merely ethical failures; they are violations of the very principles that keep systems alive. The stewardship of life therefore extends from cell biology to planetary ecology.

And yet, amid this grandeur, life remains intimate. It begins in the invisible union of molecules, grows in the warmth of a mother’s body, learns to walk, to hope, to forgive. Each personal story is a local expression of the universal drive to persist, to connect, to transcend. When we say someone has “lost the will to live,” we are describing not only biochemical exhaustion but the dimming of meaning. Spirit and physiology intertwine until the last pulse.

So, what is life? It is a self-maintaining pattern of matter and energy, open to the flow of the universe, able to transform and be transformed. It is the dance between entropy and information, between dust and breath. It is the signature of the cosmos learning to love through conscious beings. To describe it purely in formulas is to know its skeleton; to encounter it with reverence is to touch its soul.

In my own conviction as simple lim ju boo by name, or by my Chinese name -  lim ru wu, (林 如 武)  after following both microscopes and scriptures, I believe life is neither random chemistry nor magic alone. It is the language through which the universe, and perhaps its Creator - speaks coherence into chaos. Every cell, every heartbeat, every act of compassion is a syllable in that divine dialogue. When science measures, it listens to the grammar; when faith worships, it hears the music. Both are hearing the same voice.

And when the breath finally leaves, I imagine it not as extinction but translation. The molecules return to soil and star; the pattern returns to the Source that first uttered it. Between the physicist’s entropy and the psalmist’s praise, a single truth gleams: “I will praise Thee; for I am fearfully and wonderfully made” (Psalm 139:14). Life is that wonder made visible.

 

References

1. Schrödinger E. What Is Life? The Physical Aspect of the Living Cell. Cambridge University Press, 1944.

2. Prigogine I., Stengers I. Order out of Chaos: Man’s New Dialogue with Nature. Bantam, 1984.

3. Margulis L., Sagan D. What Is Life? University of California Press, 1995.

4. Kauffman S. A World Beyond Physics: The Emergence and Evolution of Life. Oxford University Press, 2019.

5. Ecclesiastes 12:7 (King James Version).

6. Genesis 2:7 (King James Version).

7. John 1:4 (King James Version).

8. Psalm 139:14 (King James Version).

9. Bergson H. Creative Evolution. Macmillan, 1911.

10. Capra F. The Systems View of Life. Cambridge University Press, 2014.

My next 3 articles spread out over next two weeks, shall be on Molecular Biology, namely: 

1. Molecular Biology: The Language of Life and Its Transformative Power Across Science,  Medicine to Forensic Investigations 

2.  Molecular Biology in Medicine: From Genes to Therapeutics  - Dedicated to the advancement of human health through molecular insight and scientific compassion.

3. Molecular Biology in Forensic Science: Unveiling Truth Through DNA in Crime Investigation with a number of examples on high profile cases in Malaysia