Tag Archives: Biology

Scientists Learn the Ropes on Tying Molecular Knots

The world is tied up in knots. They form spontaneously in swirling vortices of smoke, in long strands of yarn or hair, and in the earbud cords that somehow always tangle in one’s pocket. Even down at the molecular scale, they appear in the long chains making up some proteins, and when they arise in DNA’s twists and coils, enzymes have to help unwind them. Biophysicists study these knots to figure out how they get there and how they contribute to the behavior of those molecules.

Chemists, meanwhile, have turned their attention to molecular knots of their own making: smaller synthetic constructions assembled from joined fragments rather than tied in a single continuous biomolecular string. In their labs, they have been painstakingly synthesizing such tiny knots, … Read the rest

World’s Oldest Fossils Now Appear to Be Squished Rocks

In August 2016, a research team claimed to have unearthed evidence of life in a remote outcrop of 3.7-billion-year-old rocks in Greenland. This bold claim not only pushed back the origin of life by at least 220 million years, it also added to a growing body of evidence that challenged the standard story of Earth’s violent beginning, as Quanta Magazine reported this year in “Fossil Discoveries Challenge Ideas About Earth’s Start.” Joining a series of ancient fossil finds — as well as geological evidence from Earth and the moon — the Greenland discovery added weight to the idea that Earth was warm and watery from the outset, and that in such conditions, life emerged quickly.

But a follow-up study published in Nature last week … Read the rest