Siddharta Mukherjee - The Song Of The Cell (Penguin, 2022) ****½

Siddharta Mukherjee is a biologist, physician, researcher (Stanford, Oxford, Harvard) and author of the very popular science books "The Emperor Of All Maladies" (on cancer) and "The Gene". With his latest book - The Song Of The Cell - he takes us along for a journey into the human body to find out how our cells work together to give our body all its functions and possibilities. 

His way of presenting this is fascinating: he does this step by step, each time with some personal stories to illustrate, and always by honouring the researchers who discovered the functions he described, including what they looked like, what they struggled with (or even literally killed each other for), yet all this focused on the incredible variety and functions of cells we have in our bodies, and how they have evolved from their original egg cell to become hyperspecialised in some organ or circulating through the body. Bone cells, blood cells, brain cells, liver cells, pancreatic cells, and the zillion of other cells are presented, and how they interact, how our immune cells do their work (or not) ... and all that without going into too much technical details of biology or biochemistry or even physics. 

His biological overview is also a historical one, showing the immense progress we have made in the last decades, almost exponentially, considering how little we knew a century ago, and how we even knew less for thousands of years before. 

In his exploration of the cells in our body, and the clear explanation of all that is currently known, he leaves a lot of space for the unknown, for the deeper mysteries and areas for further discovery and research. 

Near the end of the book, he gives this summary which describes it well: 

"We are built of uni­tary blocks-extraordinarily diverse in shape, size, and function, but uni­tary nonetheless. 

Why? The answers can only be speculative. Because, in biology, it is easier to evolve complex organisms out of unitary blocks by permuting and combining them into different organ systems, enabling each to have a spe­cialized function while retaining features that are common across all cells (metabolism, waste-disposal, protein synthesis). A heart cell, a neuron, a pancreatic cell, and a kidney cell rely on these commonalties: mitochondria to generate energy, a lipid membrane to define its boundaries, ribosomes to synthesize its proteins, the ER and Golgi to export proteins, membrane­spanning pores to let signals in and out, a nucleus to house its genome. And yet, 'despite the commonalities, they are functionally diverse. A heart cell uses mitochondrial energy to contract and act as a pump. A beta cell in the pancreas uses that energy to synthesize and export the hormone in­sulin. A kidney cell uses membrane-spanning channels to regulate salt. A neuron uses a different set of membrane channels to send signals that en­able sensation, sentience, and consciousness. Think of the number of dif­ferent architectures you can build with a thousand differently shaped Lego blocks. 

Or perhaps we might reframe the answer in evolutionary terms. Recall that unicellular organisms evolved into multicellular organisms-not once, but many independent times. The driving forces that goaded that evolu­tion, we think, were the capacity to escape predation, the ability to compete more effectively for scarce resources, and to conserve energy by specializa­tion and diversification. Unitary blocks-cells-found mechanisms to achieve this specialization and diversification by combining common pro­grams (metabolism, protein synthesis, waste disposal) with specialized pro­grams ( contractility in the case of muscle cells, or insulin-secreting capacity in pancreatic beta cells). Cells coalesced, repurposed, diversified-and con­quered."

 As a physician, he not only talks about how our cells do work, but also what happens when they are out of control, when our immune system starts attacking our own body, when pancreatic cells malfunction and lead to diabetes, how cancer cells never stop growing. He is proud of the achievements, but also humble in his realisation that there is still a gigantic amount of discoveries to be made. 

"When the comprehensive list of genes that drive the growth of cancer cells were first identified in the mid-2000s, there was an exuberance that we had unlocked the key to cures for cancer.  

"You have a leukemia that has mutations in Tet2, DNMT3a, and SF3bl;' I would tell a bewildered patient. I would look at her triumphantly, as if I'd solved the Sunday crossword puzile. 

She would look at me as if I was from Mars. 

And then she would ask the simplest question: "So, does that mean that you know the drugs that are going to cure me?" 

"Yes. Soon;' I would say, with exuberance. For the linear narrative ran thus: isolate the cancer cells, find the altered genes; match it with medicines that target those genes, and kill the cancer without harming the host. 

Not that I believe that he said this to a patient in real life, but it illustrates the realisation that there is still a lot of work to be done. Biology and medical science have barely scratched the surface of what could be achieved. 

The topic of the book is one with many wonders, and the deep insight that our life on earth is truly exceptional and precious, incredibly difficult to understand and incredibly complex and fascinating. Mukherjee is a wonderful guide, and the amazing thing is that he finds the time to even write this kind of book despite all his other work as a physician and top-researcher. We can only be grateful that he shares his knowledge and enthusiasm with us.