Detail from Cytoplasm (2005) by David Goodsell, from the Molecular Landscapes series


The cell is not a factory

Scientific narratives project social hierarchies onto nature. That’s why we need better metaphors to describe cellular life

by Charudatta Navare + BIO

Detail from Cytoplasm (2005) by David Goodsell, from the Molecular Landscapes series

When you think about it, it is amazing that something as tiny as a living cell is capable of behaviour so complex. Consider the single-cell creature, the amoeba. It can sense its environment, move around, obtain its food, maintain its structure, and multiply. How does a cell know how to do all of this? Biology textbooks will tell you that each eukaryotic cell, which constitutes a range of organisms from humans to amoeba, contains a control centre within a structure called the nucleus. Genes present in the nucleus hold the ‘information’ necessary for the cell to function. And the nucleus, in turn, resides in a jelly-like fluid called the cytoplasm. Cytoplasm contains the cellular organelles, the ‘little organs’ in the cell; and these organelles, the narrative goes, carry out specific tasks based on instructions provided by the genes.

In short, the textbooks paint a picture of a cellular ‘assembly line’ where genes issue instructions for the manufacture of proteins that do the work of the body from day to day. This textbook description of the cell matches, almost word for word, a social institution. The picture of the cytoplasm and its organelles performing the work of ‘manufacturing’, ‘packaging’ and ‘shipping’ molecules according to ‘instructions’ from the genes eerily evokes the social hierarchy of executives ordering the manual labour of toiling masses. The only problem is that the cell is not a ‘factory’. It does not have a ‘control centre’. As the feminist scholar Emily Martin observes, the assumption of centralised control distorts our understanding of the cell.

A wealth of research in biology suggests that ‘control’ and ‘information’ are not restricted at the ‘top’ but present throughout the cell. The cellular organelles do not just form a linear ‘assembly line’ but interact with each other in complex ways. Nor is the cell obsessed with the economically significant work of ‘manufacturing’ that the metaphor of ‘factory’ would have us believe. Instead, much of the work that the cell does can be thought of as maintaining itself and taking ‘care’ of other cells.

Why, then, do the standard textbooks continue to portray the cell as a hierarchy? Why do they invoke a centralised authority to explain how each cell functions? And why is the imagery so industrially loaded?

Perhaps this view of the cell sounds ‘obvious’ and natural to us because it resonates with our stratified societies and their centralised institutions. But the trouble with doubling down on this kind of metaphor as a stand-in for science is that assumptions about how a cell ought to function prevent us from understanding how the cell really functions. What is more, when science projects social hierarchies onto the cell, it also reinforces the notion that social hierarchies are ‘natural’.

The projection of social hierarchies onto nature is often not deliberate. In the case of the cell, there is a long history of how it emerged. One part of the story is that when biologists began investigating chemical changes that happen in the cell, they found the metaphor of a factory quite useful. The 19th-century German biologist Rudolf Virchow, for instance, wrote that ‘starch is transformed into sugar in the plant and animal just as it is in a factory’. As researchers investigated the organelles, from the manufacture of protein in the endoplasmic reticulum to the production of energy in the mitochondria, his metaphor of ‘a factory’ guided how scientists talked about these organelles.

Another part of the story involves a different field of biology, where scientists were trying to figure out how tiny cells give rise to multicellular organisms like us. Some thought that the sperm contained a homunculus, a tiny version of the body, already fully formed. Others thought that the biological mother provided all material contribution to the embryo, while the father lent only a ‘generative force’ to propel the egg into development. Only when scientists could study the process of fertilisation under the microscope could they see that each parent contributes one cell to the next generation. But the cells were not equal. The egg was huge compared with the sperm, in humans, almost 10 million times larger in volume.

It seemed that the age-old mystery was solved, and the paternal contribution to the progeny was much less than the maternal contribution. Unless, of course, what really mattered was a tiny component present in both sperm and egg. Microscopic observations in the late 19th century revealed that when the sperm and the egg fused during fertilisation, their nuclei fused as well. The nucleus of the sperm and the egg were similar in size. Historians of science like Hans-Jörg Rheinberger and Staffan Müller-Wille have described how those early researchers began to think of the nucleus that was created when egg and sperm merged as the source of hereditary information. Biological research in the 20th century, consequently, focused much more on the nucleus, noted the physicist and feminist scholar Evelyn Fox Keller, giving short shrift to contributions from the rest of the egg.

The glorification of the nucleus and its contents, of genes as ‘information’, still prevails in the scientific discourse. In line with that, the metaphor of the cell as a ‘factory’ still dominates today.

Science is often described as objective and value-free, but philosophers of science have pointed out that values can guide the questions that scientists ask, the hypotheses they make, and the way they interpret their results. The field of feminist science studies, in particular, has called into question the sole role of the nucleus where heredity is concerned.

The nucleus, of course, does make some hereditary contribution, and we understand it in great detail. But the nucleus is only a tiny subset of the hereditary material. If we don’t even search for hereditary information in the egg cell – if we never describe that information as hereditary – we will keep propagating the idea that biological inheritance is restricted to the nucleus alone.

In parallel with feminist scholars, challenges to the old way of thinking have been mounting over the years. We now know that several other kinds of hereditary information are spread all over the cell. For instance, developmental biologists, who study how an embryo develops from a single cell, have shown that the spatial arrangement of various molecules in the cytoplasm of the egg cell helps to determine where the head and the tail of the growing organism will be, how the front side will develop differently from the back side, and so on. The cytoplasm of the egg doesn’t just ‘nourish’ the nucleus but contains coded information passed down from generations before.

These days, philosophers of biology like Marcello Barbieri are trying to understand what the word ‘information’ even means in the context of the cell. In biology, the genetic code is the only code we seem to hear about, but is that actually fair – or is it a bias emerging from the hierarchical societies that scientists are part of?

In his book The Organic Codes (2009), Barbieri writes about the assumptions that preceded the ‘discovery’ of the genetic code in the nucleus as the pinnacle of it all. The idea of information encoded in genes directing the construction of proteins came first. And it was only following this prediction that DNA was experimentally discovered and conceptualised as a ‘genetic code’.

The nuanced interaction between cellular organelles is a direct challenge to the top-down order of a factory

Barbieri calls this discovery a self-fulfilling prophecy. Since scientists never made similar assumptions about ‘codes’ in the cell’s cytoplasm, they weren’t as keen to look for them. We are told that the genes contain blueprints to make proteins. However, genes do not contain all the information needed to make proteins. They only specify a one-dimensional protein chain; the three-dimensional structure that the proteins take, which is vital for their function, is determined by the cellular environment as well. Further, the way proteins behave also varies with where they are in the cytoplasm. The genetic ‘information’, on its own, is nowhere near enough for the cell to function.

More insights about information in the cytoplasm come from biologists who study how the cellular organelles interact with each other. We now know that the linear ‘assembly line’ that textbooks construct does not remotely capture the many functions of organelles in the cytoplasm or the many different ways in which they ‘talk’ to each other and influence each other’s behaviour. The nuanced interaction between cellular organelles, in fact, stands as a direct challenge to the coercive, top-down notion of order that a centralised factory suggests. The ‘departments’ in the ‘factory’ seem to be communicating with each other and giving each other orders without keeping the ‘head office’ in the loop.

All of this coded information in the cytoplasm leads us to ask: why do modern textbooks, which are supposed to present the standard, well-accepted knowledge of the day, continue to portray the cell as hierarchical in structure? Why do science journalists continue to refer to the codes and programs of genes in the nucleus when discussing how life develops and evolves?

I believe that the hold of the centralised view comes from how it resonates with the human social order. The nucleus providing instructions and the cytoplasm performing the labour of ‘nurturing’ sounds ‘natural’ and even ‘obvious’ in a patriarchal society. The central nucleus ordering its ‘underling’ cytoplasm to actually carry out tasks sounds obvious in a class-stratified society.

Would scientists coming from different social situations come up with a different view of the cell?

Possibly. Think about how the biologist E E Just viewed the cell. Just worked on the peripheral cytoplasm of the early egg cell. In his book The Biology of the Cell Surface (1939), he held that cytoplasm was capable of ‘self-regulation and self-differentiation’, and lamented the prominent view of development that relegated the cytoplasm to a mere nurturing shell. Just was also a Black scientist living in the early 20th-century United States.

An African American scientist at work in a lab with a microscope. The image is an older print within a photo album
Ernest Everett Just pictured in 1914, author of The Biology of the Cell Surface. Courtesy University of Chicago

The developmental biologist Scott Gilbert has analysed Just’s science in the context of his social position. The standard view of development holds that the instructions for development are located in the central genes. Contrast this with Just’s view that the cytoplasm had ‘potential’ for ‘development’ and that the function of the nucleus was to add or remove ‘obstacles’ from its path.

Just’s cytoplasm is able to function without explicit instructions from the nucleus. It can govern itself and develop if only the government would remove the ‘obstacles’ in its path. Historically, the majority of scientists have been male, upper class, and belonging to the dominant castes and races. It is possible that the social position of scientists helped them relate to the notion of a nucleus that continues discharging instructions while taking for granted the knowledge and skills required in actually doing the work. The Nobel laureate David Baltimore described genes as the ‘executive suite’ and the cytoplasm as the ‘factory floor’. The executive suite appears more valuable and deserving of more remuneration, while the toiling masses on the factory floor are thought to be merely executing the instructions, undervaluing the wealth of explicit and tacit knowledge and skill.

You might argue that ‘the cell as a factory’ is only a metaphor. You could say that scientific metaphors should be judged based on how useful they are, and no metaphor is perfect. The ‘cell as a factory’ metaphor has undoubtedly been useful in guiding the trajectory of cell biology. I completely agree with all of this. What I wish to point out is the lack of other metaphors. Precisely because no metaphor is perfect, we should employ multiple metaphors, each explaining certain aspects of the cell. Unfortunately, the centralised and hierarchical metaphor, so pervasive in textbooks, is often the only one for the internal workings of the cell.

One alternative metaphor for the cell nucleus, I tentatively suggest, could be a ‘collaborative notebook’. The cell keeps this notebook, and all the cell’s components use it to keep track of their activities and help maintain the cell. The cell ‘writes’ in the notebook, writes in the ‘margins’ and ‘refers’ to its own notes. Cellular organelles sense each other’s needs and take ‘care’ of each other. While the ‘factory’ metaphor attributes control and information to the nucleus, the ‘nucleus as a collaborative notebook’ shows agency on the part of the cell. While the factory metaphor makes the cell seem obsessed with ‘production’, alternative metaphors can highlight the mutual aid among the cellular components and the labour of maintaining the cell.

Why do we find a lack of such metaphors in scientific discourse? Why does it seem like too much anthropomorphism to talk about organelles taking ‘care’ of each other but not when we talk about genes ‘instructing’ their underlings? Could this selective anthropomorphism reinforce the ideology of centralised control through the accepted scientific metaphors? If that is so, we will fail to capture how the cell works until we check our assumptions. If we want to comprehend the unruly structure that is the cell, we need to change the lenses through which we view the world.

Beyond how the cell works, this discussion has wider implications for science. The cell is not the only natural system described using centralised metaphors. We talk of insect societies having ‘queens’ and what is literally called a ‘caste’ structure. We have ‘alpha’ primates who ‘lead’ the group and keep ‘harems’.

When values interfere with science, the quest for truth and accuracy is put at risk

The reason we find centralised functioning everywhere is not necessarily because it is everywhere. It just appears to be everywhere because of the lens through which we view the world. When scientific narratives, using all the authority of science, project the social hierarchy onto nature, they can reinforce the same hierarchy as ‘natural’. The centralised model from cells to animal social groups suggests that everything in nature is centralised, and that centralisation works. The ‘truth’ about nature is influenced by our values, and this ‘truth’ can then play a role in doubling down and reinforcing the same social values in the world.

Why should it matter, you might ask. After all, regardless of how nature is, what is considered as moral in human society should be distinct. Violence is present in nature, but that does not make it ‘right’.

Nevertheless, the science historian Lorraine Daston in Against Nature (2019) has shown that arguments about what is natural have always carried moral weight. What is natural may not determine what is moral, but it can influence it. Another important aspect, of course, is the concern about an accurate depiction of nature. If the projection of social inequalities onto the cell distorts our understanding of the cell, we should try to be mindful of this projection – because understanding the cell is vital to progress in the life sciences and to human health.

How science conceptualises the cell also gives us insight into how we think of scientific objectivity. We often think that, when values interfere with science, the quest for truth and accuracy is put at risk. Scientists are supposed to leave their values and beliefs outside their labs. However, research in feminist science studies suggests otherwise. One does not necessarily need to be free of values to do good science, but denying their influence undermines the quality of scientific work. Instead of denial, reflecting on values and biases would help researchers steer clear of the pitfalls. Self-reflection can help scientists identify how their values are shaping their science, and think of better experimental designs that could ‘catch’ their assumptions before they compromise results.

Science is undoubtedly a human endeavour. The feminist philosopher Donna Haraway describes science as a conversation between partial perspectives that each individual gets from the vantage point of their position. As Just’s science shows, people with different life experiences might have different perspectives and may ask different questions. Admittedly, the connections between scientists’ backgrounds and their work are not always so direct. But the social position of scientists can still serve as one of the factors that influence their work. We often say science is self-correcting. We think that science changes its views when new information comes to light. But this new information doesn’t emerge from a vacuum. It doesn’t emerge only from new techniques. It is also generated when people with different perspectives take a look at the same data through different lenses. While diversity and representation are important in their own right from the perspective of equity, diverse perspectives would benefit science most of all. Objectivity is not an individual burden but a collective one.

If we are unable to conceive of the cell, the basic unit of organisms like ours, without coercive hierarchies, we will never fully appreciate the complexity of nature. If we fail to imagine society without a centralised authority, we will find it difficult to understand or empower the oppressed. Unless we reflect on our assumptions, our science will be loaded with so many landmines it may never unravel all the mysteries of life.