Big news! Our new book, "Making the Modern Laboratory," is now available for pre-order. It is a stunning, 504-page hardcover book that explains how the research laboratory, and everything in it, came to be. Did you know that the modern micropipette was invented by a German postdoc so frustrated with mouth pipetting that he ditched his lab for two days until could return with a prototype? Or that an 18th-century scientist sewed tiny taffeta pants for male frogs to determine whether or not semen was essential for fertilization? These stories and hundreds more are told in the book, which has a hard cloth cover and is printed in full color on Arena Natural Rough, a textured, uncoated paper made by Fedrigoni. The book is also finished with colored endpapers, thread-sewn binding, and a squared spine. It is priced at $49 and worth every penny. Learn more and order: press.asimov.com/articles/mo…

Mitochondria are alive. They carry their own genomes and express their own genes within their lumens, an internal pocket of watery space, using biomolecules distinct from the cell’s nucleus. Mitochondria also replicate and divide through binary fission, much like bacteria. If one considers bacteria as living entities — and all biologists seem to — then it is impossible to explain why mitochondria are not. From a thermodynamic perspective, mitochondria take in low-entropy inputs from their host cell, such as glucose or fatty acids, and expel high-entropy outputs, including carbon dioxide and water. Mitochondria also pump out protons through their inner membrane to maintain an out-of-equilibrium thermodynamic balance, using the resulting gradient to produce the ATP molecules that fuel cellular functions, from DNA replication to protein synthesis. From the molecular biologist’s perspective, a mitochondrion’s role is not limited to simple energy generation, either. Mitochondria also process information and interact with their environment, much like a human cell. They monitor steroid hormones, oxidative stress, heat, ATP levels, secondary metabolites, and many more molecules floating through their environment, the cell’s cytoplasm. Mitochondria then use this information to precisely control cellular functions. For example, when a virus invades a cell, the mitochondria are critical in sensing the intrusion and signaling a host cell to undergo programmed cell death to halt its spread. And finally, mitochondria grow and reproduce in a manner distinct from the host’s replication process. Mitochondria independently copy their circular genomes, known as mitochondrial DNA, and divide through binary fission. Notably, mitochondrial replication has several distinct properties from those observed during human cellular replication. Mitochondrial DNA mutates 100-1,000 times faster than the human genome and these mutations can significantly alter a mitochondrion’s fitness, thereby changing the fitness of its host cell. Mitochondria are thus agents of — and subject to — the forces of evolution. Despite all this evidence, the main case made against mitochondria being alive is that they do not perform all of these functions independently, as they must be embedded within the cytoplasm of a host cell to function. However, such an argument is logically inconsistent because, by this same logic, most organisms on Earth would not be considered “living.” After all, nothing in biology lives in isolation from its environment. Read the full essay by Liyam Chitayat: asimov.press/p/mitochondria