Published in Synapse: The UCSF Voice

On the politics of metaphor in science education, and what biology might learn from queer kinship.

By Yoni Tamang

The metaphor most commonly used by educators to describe the selective permeability of the cell membrane is border control. You’ll remember the cliché from biology class: the cell is a city and the organelles perform civic functions. Lysosomes take out the garbage, ribosomes mint currency, the smooth and rough endoplasmic reticulum provide highways, while the dictatorial nucleus keeps order. The membrane, cast as the city’s border, maintains homeostasis by keeping the bad stuff out and the good stuff in.

Aside from begin a gross over simplification of the cell, I wonder: do these metaphors trivialize border violence? Does the framing reveal something important about the cell behavior? The Unite States’ borderlands are not only geographies where our government enacts its security policies, but also symbolic territories written into our flesh. Do we even have an alternative metaphor for microbes? Or are we trapped into imagining cellular life through conquest?

I know inventing new biological metaphors will not solve the dilemmas of current immigration politics, but I do believe new stories matter. Rethinking metaphor is part of decolonizing our flesh, and a worthwhile task for art.

So here’s my counter-story of selective permeability:

The two great evolutionary leaps on earth—the emergence of eukaryotes from prokaryotes, and of multicellular organisms from single cells—happened not through rigid borders but through porous ones. They came from accidents: a bacterium engulfed another, failed to destroy it, and instead thrived on its energy. Together, they passed on a singular genome, a blueprint for cooperation. Later, groupings of unicellular organisms lingered in liminal states—neither fully apart nor fully fused—until they stumbled into multicellularity. Evolution advanced through boundary failures.

We owe our eukaryotic lives to indigestion and lazy policing, to symbiosis in the face of disruption. I love the idea of “chosen family,” so why not expand it to organisms, geographies, metabolisms, and taxa that threaten our fantasies of purity and power?

Because my body is not made of microscopic dictatorships with border police at every gate. My body is a contact zone, the product of billions of years of unlikely kinship among the strangest partners.