Adenine is a nucleobase, which is a component of nucleotides, the basic building blocks of DNA and RNA.

Adenosine triphosphate (ATP) is a complex organic chemical that is involved in energy transfer within cells.

DNA, also known as deoxyribonucleic acid, is a molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses.

DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome.

Enzymes are macromolecular biological catalysts that accelerate chemical reactions.

Guanine (symbol G or Gua) is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine (uracil in RNA).

A hydrogen bond is a type of chemical bond that occurs between a hydrogen atom and an electronegative atom, such as nitrogen, oxygen, or fluorine.

NASA (National Aeronautics and Space Administration) is an independent agency of the United States federal government responsible for the country's civilian space program and for aeronautics and aerospace research.