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

by Siddhartha Mukherjee

The pioneering studies of Palade, Porter, and Claude threw open a new world of subcellular anatomy. The twinning of two ways of seeing—microscopy and biochemistry—was synergistic. As biologists used these methods on cells, they found dozens of such functional, anatomically defined subcellular structures. The Belgian biologist Christian de Duve, yet another Rockefeller Institute scientist, discovered an enzyme-laden structure called a lysosome. Like a cellular “stomach,” it digests worn-out cellular parts, as well as invading bacteria and viruses. Plant cells contain structures called chloroplasts, the sites of photosynthesis, the conversion of light into glucose. Chloroplasts, like mitochondria, carry their own DNA, again suggesting an origin in microbes that were engulfed by other cells. There is a membrane-bound structure called a peroxisome, another of de Duve’s discoveries, where some of life’s most dangerous reactions—for instance, the oxidation of molecules—is sequestered, and where hydrogen peroxide, an intensely reactive chemical, is generated. Were the peroxisome to open up and release its internal poisons, the cell would be attacked by its own reactive contents. It is the chalice, filled with poisons to metabolize other poisons, that the cell keeps carefully closed.