This image illustrates the chemical structure of a purine molecule, highlighting the numbering of the carbon and nitrogen atoms. The purine structure consists of a pyrimidine ring (positions 1 to 6) ...

Just as countries import a vast array of consumer goods across national borders, so living cells are engaged in a lively import-export business. Their ports of entry are sophisticated transport ...

image: Three-dimensional structure of the yeast Mec1-Ddc2 complex, a homolog of human ATR-ATRIP. The genomes of eukaryotic cells are under continuous assault by external and internal factors. All ...

Scientists have discovered that a sample of the Ryugu asteroid collected by Japan's Hayabusa 2 spacecraft contains the nucleobases adenine, guanine, cytosine, thymine and uracil, the building blocks ...