Cells, gels and the engines of life: A New Unifying Approach to Cell Function 

by Gerald Pollack

I have some questions about the standard cell theory. The main question is the theory of ion pumps. Active ion pumps are used to maintain concentration gradients inside and outside cells. I don’t have a sense of the magnitude of energy cost. But intuitively I feel it must be very energy intensive. Is there a more economic way to maintain such cellular structure?

I searched for some answers on the internet. Initially I found the name of Gilbert Ling. But his writings are too technical for me, a person with little relevant background. Later I found this book by Gerald Pollack. It introduces the ideas of Gilbert Ling and others in a very intuitive way.

The book can be roughly divided into two halves. The first half is about cell structure. The second half is about cell function. The theory of cell structure is association. The theory of cell function is phase transition. Let me explain these ideas briefly.

A Na+ ion is smaller than a K+ ion. Since a Na+ ion is smaller, it has stronger electric attraction to water molecules, which are polarized, than a K+ ion. As a result, a Na+ ion, together with the attracted water molecules, as a unit, is larger than the unit of K+ and associated water molecules. This is the main idea of association principle. We need to look at ions and atoms in association. We can’t treat them as independent particles.

Most proteins are negatively charged. There is a natural affinity between proteins and cations, such as Na+ and K+. But the levels of attraction are different. A K+ ion unit (together with associated water molecules), being smaller than a Na+ ion unit, has stronger affinity with proteins. There are a lot of proteins inside cells. They attract more K+ ion units than Na+ ion units. This explains why the concentration of K+ inside cells is higher than the concentration of Na+. It is a simple explanation. It doesn’t need energy intensive ion pumps. This is a brief summary of the first six chapters.

Chapter seven is about cell potentials. The explanation is less convincing to me. I have to reread it later. Overall, the first seven chapters constitute the first half of the book, which is about the cell structure.

The second half is about the mechanism of the cell functions. It is phase transition. Let me briefly go over its intuition. 

Suppose the temperature of the water is at 99 degree. You turn on the heat a little bit. The water temperature rises to 100 degree and water boils. The boiling water generates a lot of steam, which has tremendous propelling power. At phase transitions, great powers are released, which can be used to perform various cell functions.

Phase transitions can be triggered by the changes in temperature, in electric charges, or ph levels. The idea is that many parts of cells are near phase transition conditions. A small change of the environment, such as the addition of a small number of ions, will generate phase transitions and hence cell actions. A protein filament can be in a coiled state or extended state. The transition from the extended state to coiled state represents muscle contraction. The transition to the other direction represents muscle relaxation. The idea seems to make sense.

The book contains many examples that make cellular functions much easier to understand and much less mysterious. I will go over some examples about ions.

Most proteins are negatively charged. Most messenger cells, such as histamine and adrenaline,   are positively charged. Positive charged messenger cells have an easier time to connect with proteins, which are often negatively charged.

Divalent ions, such as Ca2+, can act as zippers, to seal two protein structures. Two positive charges of Ca2+ can attract two different protein molecules and seal them together. That is why Ca2+ ions are important in controlling the operation of molecular gates and channels. Before I don’t understand what is special about Ca2+, why Na+ or K+ can’t perform the same functions.

This book introduces a non-orthodox way to understand cell structure and functions. When one presents a non-mainstream theory, he has to make extra effort to make his message clear. Whether you agree or disagree with his ideas, you can learn a lot from his writings.