A Fundamental Error in Biology

On problems with membrane pumps and an alternative theory nearly forgotten

It's February 2024, and I'm navigating back to Saint Louis from upstate New York, where I've just finished a crash course in wet-lab biology. I feel excited and confident. I settle into the drive and my phone rings. It's a complete stranger recommended by a friend who sensed we needed to talk. At the time, this person was pursuing his PhD; however, he has since dropped out. Minutes into our conversation, he bluntly challenged one of the foundational assumptions underpinning my entire scientific trajectory.

When I am talking to someone who is telling me I am wrong, I don't often see the point in arguing. Instead, I listen intently. There is much more to learn by figuring out where they may be right and filtering out the rest. In this case, the upheaval is dramatic.

I've spent a year thinking about this conversation and come to the conclusion that decades of accepted wisdom in cell biology is fundamentally flawed.

MPT Primer

Membrane pump theory (MPT) is the widely-accepted concept that cells maintain their ion gradients primarily through active transport, using energy-consuming protein pumps embedded in the cell membrane. The most well known example is the sodium-potassium ATPase, which pumps sodium ions out and potassium ions into the cell, establishing electrochemical gradients essential for functions like signaling and nutrient transport.

Although Jens Christian Skou's discovery of the sodium-potassium ATPase in 1957 provided the first direct biochemical evidence for these protein pumps, the idea itself wasn't new.¹ Some scientists had theorized the existence of an active pumping mechanism because cells display ionic gradients that passive diffusion alone can’t explain. For decades prior to Skou's experiments, researchers were actively searching for a specific biochemical mechanism that could account for these gradients.

Jens was originally curious how nerve cells transmitted signals, and specifically, how ions such as sodium and potassium moved across their membranes in response to local anesthetics. Working quietly at Aarhus University in Denmark, he chose crab nerve cells for how robust and therefore easy they were to work with. Day in and out he isolated membranes from nerve cells and experimented with the conditions under which the enzyme activity of ATP hydrolysis occurred.

In doing this Skou noticed that ATP breakdown didn’t appear to be random but rather intensified when sodium and potassium ions were present together. Following this, Jens spent months testing different combinations of ions, always coming back to the conclusion that this enzyme didn’t just burn ATP; it seemed specifically designed to exchange sodium for potassium ions.

He published his results in 1957² cautiously laying out what he'd found: a membrane-bound ATPase that directly linked ATP energy to active ion transport. Over time, scientists around the world recognized the potential implications of Skou’s work. By the late 1960s, his discovery had reshaped cellular physiology, providing a simple biochemical basis for understanding everything from nerve conduction to heart function.

Subsequent evidence seemed to reinforce membrane pump theory by directly linking ATP hydrolysis to ion movement. X-ray crystallography even provided detailed images of pump proteins like the sodium-potassium ATPase, although these represent static, solid-phase snapshots rather than the dynamic fluid-phase realities of living membranes.

Subtle contradictions persisted despite MPT’s growing acceptance. Researchers like Troshin observed that ions behaved differently inside cells compared to outside, suggesting distinct intracellular water phases. Ernst documented cases of potassium retention within resting muscle cells independent of active pumping. Gilbert Ling, through meticulous energy-balance studies, argued compellingly that the energetic demands of classical sodium pumps far exceeded the energy cells could realistically supply from ATP alone.

These contradictions lingered as unanswered questions, quietly undermining the authority of membrane pump theory and setting the stage for a more comprehensive model.³

Life as Jell-O

As I'm struggling to wrap my head around the counterargument, my new friend on the phone offers a simple analogy: Biologists tend to think of the cell as a water balloon, enclosed by a firm membrane that, if punctured, would instantly lose its contents into the surrounding environment. He argues instead that this perspective fundamentally misunderstands the living state. Rather than a water balloon, he says, think of the cell as Jell-O—a structured, gelatinous colloid composed primarily of proteins, structured water, ions, and other molecules arranged in a three-dimensional matrix. In this model, cellular stability and ion distribution aren't just maintained by energy-intensive pumps at the boundary; they're governed by internal structural interactions among proteins, water molecules, and solutes. Instead of relying solely on an energetically costly process at the perimeter, the Jell-O analogy suggests the cell itself inherently creates and maintains order from within.

If membrane-bound pumps are truly the main way cells maintain ionic gradients, then as cells grow larger, the energy required to sustain those gradients through active pumping would skyrocket and become impractical. Although somehow large cells like oocytes and giant bacteria manage to maintain stable ionic conditions without a proportionate spike in metabolic costs to drive their pump activity.⁴ This should serve as a strong hint that something more internal must be at play.

This idea of an internal explanation was not new at the time of MPT's rise to prominence. In fact, it predated it.

In the 1930s, a Nobel laureate named Albert Szent-Györgyi introduced an idea that would become foundational later when he described intracellular water as "liquid ice," suggesting that this structured form of water was intrinsically different from ordinary liquid water. According to Szent-Györgyi, this structured water interacted strongly with proteins, creating a cohesive internal environment capable of coordinating cellular activities far more efficiently than random molecular collisions could explain.⁵

Building upon this in the early 1960s, a Soviet physiologist named Nasanov noticed that diverse stimuli, when exceeding a certain intensity, lead to the same universal changes in physiochemical properties including the structure of the water inside the cell. This led him to introduce his "denaturational hypothesis."⁶ In it, he proposes that structural changes in proteins cause these global changes in order to facilitate adaptation.

A student of Nasanov’s named Troshin took these ideas further throughout the 1960s and 1970s by studying how ions behave within living cells in response to different stimuli. In doing this Troshin demonstrated that ions didn't behave as freely inside cells as they did outside.⁷ He found that the cell's interior water had different properties, behaving more like a gel than a simple fluid. On this basis he formulated what became known as the Troshin equation. His research challenged membrane pump theory directly by showing that the internal cellular environment itself inherently controlled ion distribution, independent of constant energy expenditure from membrane pumps.

Next in line to continue this line of inquiry was Gilbert Ling in the mid-to-late 20th century.

"So you like Gilbert Ling, is he your guy?"

By this point you might be curious who was on the other side of this phone call. If you'd like you can listen to this podcast with him where the interviewer himself opens on the conversation with the above quote. Anyways, I digress here. I've been thinking about this interaction for the better part of a year, and updating my world model accordingly. Since raising money for my biotech and getting into more of the hands on work related to these mechanisms we’re talking about, I became even more radicalized in the direction that perhaps the membrane theory that's being taught in our textbooks today as ground truth is fundamentally wrong. One of the first to claim this from its earliest stages of acceptance was Gilbert Ling.

Gilbert Ling was a Chinese-American physiologist trained originally as a biochemist. Early in his career at the University of Pennsylvania, Ling developed the "Ling-Gerard microelectrode," a tool that enabled researchers for the first time to measure the electrical potentials inside living cells accurately. This invention provided a foundation for modern electrophysiology, paving the way for advances in understanding cellular bioelectricity.

Before developing his flagship hypothesis, Ling’s research primarily focused on bioelectric phenomena and ion distributions in living cells. He makes mention in multiple interviews⁸ that his career trajectory change was in part serendipitous. Ling was invited to give a lecture on the sodium-potassium pump and when he delved into the literature to prepare his talk, he discovered multiple inconsistencies and unresolved contradictions at the heart of Membrane Pump Theory.

Ling's instinct pushed him to reconsider basic assumptions about how cells maintained ionic gradients and organized their internal structures, ultimately leading him to propose a radically different understanding of cellular life.

Associating, Inducting, Hypothesizing

Ling formally introduced the Association-Induction Hypothesis (AIH) in 1962.⁹ At its heart, AIH suggests that cellular ion distributions are governed not by energy-intensive membrane pumps, but by the intrinsic structural properties of proteins and their interactions with water and ions within the cell. Rather than passive structures, proteins act as dynamic matrices possessing numerous cooperative binding sites. These sites selectively adsorb ions, creating a structured, gel-like internal environment markedly different from the simple aqueous solutions envisioned by conventional biology.

According to the AIH, intracellular water forms highly structured layers around proteins, similar to Szent-Györgyi's concept "liquid ice.” This serves to selectively exclude sodium ions while attracting potassium ions due to sodium’s larger hydration shell which makes it energetically unfavorable. Potassium, having the same charge but a smaller hydration shell, interacts favorably with negatively charged protein surfaces. This selective ion affinity inherently creates the cell's internal negative charge without continuous ATP-driven pumping. Ion movement in and out of cells can thereby be explained through protein conformational changes that dynamically adjust protein-water-ion interactions.

But what about ion channels? Surely they must have a role, right? The AIH argues these channels alone don't establish or maintain ionic gradients. They're more like carefully controlled doors allowing movement when needed, rather than the source of ionic separation itself. The real heavy lifting comes from the structured water and protein matrices inside cells, not the transient opening and closing of membrane-bound gates.

Ling supported his hypothesis through decisive experimental evidence. In one experiment, he amputated the ends of frog muscle cells, effectively removing the functional membrane pumps entirely. MPT predicts that sodium would flood into these cells, disrupting ion balance within seconds. Instead, Ling observed that these cells continued to maintain their ionic gradients for hours contradicting one of MPT’s foundational assumptions.

Ling further demonstrated how ouabain, a compound classically believed to disrupt sodium-potassium ATPase pumps, still altered sodium-potassium balance even in these membraneless cells. Rather than inhibiting nonexistent pumps, ouabain acted by altering the intrinsic affinity of intracellular proteins for sodium and potassium ions. This indicated clearly that ionic balance was controlled from within, by protein-ion interactions, not by membrane-bound pumps.¹⁰

To provide definitive support, Ling proposed simple experiments measuring how isolated proteins cooperatively adsorb ions, demonstrating conclusively that proteins alone could account for ionic specificity and distribution without relying on membrane pumps. He also showed that structured proteins, when placed in dialysis setups, directly influenced solute distribution and water behavior, further emphasizing the protein-water-ion triad central to AIH.

Ling's findings didn't merely challenge MPT; they offered compelling answers to longstanding anomalies, such as how cells sustain ionic gradients under conditions of reduced metabolic energy, or how exceptionally large cells maintain ionic stability without prohibitive energy demands. AIH accounts for these observations and provides a coherent framework without resorting to complex modifications of pump-based theories.

No AIH, No MRI

Further validation of AIH emerged through Raymond Damadian’s work in nuclear magnetic resonance (NMR), which directly contributed to the invention of Magnetic Resonance Imaging, better known by its acronym, MRI. Damadian was influenced by earlier NMR studies conducted by researchers like C.F. Hazlewood and D.C. Chang, who showed that there were significant changes in intracellular water structure associated with cancer. This led him to hypothesize that variations in intracellular ion and protein interactions could alter the relaxation times of water molecules, which could be measured by NMR to provide a non-invasive cancer screening method.

At the time, conventional wisdom suggested that MRI alone was insufficient for reliably distinguishing cancerous tissue from healthy tissue, making contrast agents or complementary imaging methods such as CT scans or X-rays necessary. Damadian's insight, rooted in the AIH, proposed that the cellular environment itself could intrinsically influence how water protons relax back to equilibrium after exposure to a magnetic field.

Specifically, Damadian recognized that structured water would exhibit distinct NMR relaxation properties compared to less structured, free water. Cancerous cells, characterized by altered intracellular protein configurations and ion distributions, would therefore display measurably different relaxation times. Damadian’s initial experiments demonstrated these clear differences between normal and cancerous cells, confirming that intrinsic protein-water structuring significantly influenced NMR signals.

This conceptual breakthrough did not just enhance NMR applications, it shifted the theoretical understanding of MRI’s potential. Instead of needing to rely on external contrast agents or invasive techniques, Damadian’s work showed that MRI could differentiate tissues based on their internal biochemical and biophysical environments. This insight bridged the theoretical predictions of Ling’s AIH and practical clinical imaging to transform MRI from a purely anatomical tool into one capable of detecting subtle physiological differences.

Understanding the profound but disputed significance of Ling’s hypothesis in medicine, Damadian became one of Ling’s key proponents, stepping in to personally support Ling’s research when traditional sources withdrew due to mainstream doubt.¹¹

The state of the field

Throughout history, science has evolved by challenging and replacing established paradigms with new models that better explain observed phenomena. The geocentric model, which placed Earth at the universe's center, was superseded by Copernicus' heliocentric model, positioning the Sun at the center. Newton's laws of motion and universal gravitation provided a comprehensive framework for understanding physical phenomena, which was later refined by Einstein's theory of relativity to account for observations at extreme scales. It took decades for Einstein's theories to become widely accepted within the scientific community.

If a figure with ideas as revolutionary as Einstein's emerged today, the entrenched dogma within the scientific community might delay their acceptance by even longer. Science today suffers from a dangerous complacency: a sense that we already understand all the fundamentals. Historically, scientific progress follows a familiar pattern: we create models that seem to explain phenomena definitively, then invent new tools that allow us to observe deeper into reality, only to find that our cherished models no longer hold true.

Despite its explanatory power, the Association-Induction Hypothesis has not yet achieved widespread acceptance. Gilbert Ling passed away in 2019 at age 99, without witnessing mainstream recognition of his life's work. Nonetheless, his theories continue to inspire and influence researchers dedicated to understanding cellular physiology at a deeper, more integrative level.

Few scientists are actively building upon Ling’s foundations, merging AIH concepts with modern developments in biophysics and molecular biology. I can say this though: there are at least a handful in Saint Louis, Missouri.

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For further reading on this, I suggest Laurent Jaeken's The Coacervate-Coherence Nature of Life which provided the foundational context for much of this blog. Having extensively reviewed the writings of Ling and his contemporaries, I consider Jaeken’s book the clearest and most insightful single starting point for understanding and engaging with these ideas.

Thank you @anabology for hours upon hours of conversations on these subjects as well.

Never be complacent.

-Benjamin Anderson

Follow me on X: @consciousrepo

Nostr: ben@buildtall.com

1. Ling G. History of the membrane (pump) theory of the living cell from its beginning in mid-19th century to its disproof 45 years ago--though still taught worldwide today as established truth. Physiol Chem Phys Med NMR. 2007;39(1):1-67. PMID: 18613639.

2. SKOU JC. The influence of some cations on an adenosine triphosphatase from peripheral nerves. Biochim Biophys Acta. 1957 Feb;23(2):394-401. doi: 10.1016/0006-3002(57)90343-8. PMID: 13412736.

3. But wait, you’re asking: don’t these membrane pumps actually exist? Well, yes. The sodium-potassium ATPase and other similar proteins are real, functional proteins embedded in cell membranes, and their biochemical activity is undeniable. However, their significance might be drastically overstated. Instead of serving as the cell’s primary mechanism for maintaining ionic gradients, perhaps these pumps function more subtly. The question isn’t whether pumps exist but how essential they truly are. Additional fun fact: a basic biology textbook will tell you that 50% of the cell membrane is comprised of protein by weight. Maybe this doesn’t seem like a lot to you. I was shocked when I reread this idea after being exposed to these ideas.

4. McCarty, N. “What Limits a Cell’s Size?” Asimov Press (2025). DOI: 10.62211/97to-41re

5. Szent-Györgyi, A. (1956). Bioenergetics. Science, 124(3227), 873-875.

6. Nasonov, D. N. (1959). Local reaction of protoplasm and gradual excitation.

7. Troshin, A. S. (2013). Problems of Cell Permeability: International Series of Monographs in Pure and Applied Biology: Modern Trends in Physiological Sciences, Vol. 26.

8. Here is an excellent 4 hour podcast with him I’d recommend.

9. Ling GN. A Physical Theory of the Living State: An Investigation of the Relation Between the Physiological and the Physical-Chemical States of Living Matter. New York: John Wiley & Sons; 1962.

10. Ling GN. How does ouabain control the levels of cell K+ and Na+? by interference with a Na pump or by allosteric control of K+-Na+ adsorption on cytoplasmic protein sites? Physiol Chem Phys. 1973;5(4):295-11. PMID: 4543156.

11. Chang DC. A new understanding on the history of developing MRI for cancer detection. arXiv preprint arXiv:2405.00053v2 [physics.soc-ph]. 2024. doi: 10.48550/arXiv.2405.00053.