The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

It is the cell’s trash compactor, the proteasome, where proteins go to die. Proteasomes degrade proteins into their constituents and eject the chewed-up pieces back into the protoplasm, completing the cycle of synthesis and breakdown.

Why did we ever leave the single-celled world? Why did “we” become “we”—that is, multicellular organisms? Take a yeast cell or some species of single-celled algae. These single cells, or modern cells, as biologist Nick Lane calls them, possess virtually all the features of the cells of vastly more complex organisms, including humans. They are abundant, fiercely successful in their environments, and can thrive in diverse places on Earth. They communicate with one another, reproduce, metabolize, and trade signals. They possess nuclei, mitochondria, and most of the cellular organelles that make an autonomous cell function with extraordinary efficiency. Which begs another question: Why on earth did they choose to form multicellular organisms?