Oxygen at life's boundaries

摘要

Proteins are made of amino acids. But amino acids are made of atoms. Exploration of this self-evident principle opens up fresh perspectives on the evolution of biological membranes and multicellular life. For many microorganisms, one cell is adequate; for some plants and animals, billions are scarcely enough. But whatever the number, the cell is the fundamental unit of living matter, and is invariably delineated by a membrane — the plasma membrane — that is a selective barrier separating the inside from the outside.