He was awarded the Nobel Prize for Physiology or Medicine in 1910 for his work in determining the chemical composition of nucleic acids, the genetic substance of biological cells.

Kossel isolated and described the five organic compounds that are present in nucleic acid: adenine, cytosine, guanine, thymine, and uracil.

These compounds were later shown to be nucleobases, and are key in the formation of DNA and RNA, the genetic material found in all living cells.

As a youth, Kossel attended the Gymnasium at Rostock, where he evidenced substantial interest in chemistry and botany.

At the time, Hoppe-Seyler was intensely interested in research concerning an acidic substance that had first been chemically isolated from pus cells by one of his former students, Friedrich Miescher, in 1869.

During the period 1885 to 1901, he was able to isolate and name its five constituent organic compounds: adenine, cytosine, guanine, thymine, and uracil.

These compounds are now known collectively as nucleobases, and they provide the molecular structure necessary in the formation of stable DNA and RNA molecules.

[1] With his distinguished English pupil Henry Drysdale Dakin, Kossel investigated arginase, the ferment which hydrolyses arginine into urea and ornithine.

[2] Another of Kossel's students was American biochemist Edwin B. Hart, who would later return to the United States to participate in the "Single-grain experiment" (1907–1911) and be part of research teams that would determine the nutritive causes of anemia and goiter.

[1] Kossel contributed to early issues of the Zeitschrift für Physiologische Chemie (Journal of Physiological Chemistry).

This publication was founded by his professor and mentor, Felix Hoppe-Seyler, in 1877, the same year that Kossel started work as his research assistant.

[citation needed] Albrecht Kossel was apparently not greatly interested in politics, but in 1914 he did not sign the propaganda Pronunciamento of German professors at the start of the war.

He refused this demand, would never declare untruths as truths[1] Through his marriage to Luise, Kossel was related to several prominent Americans, including soil science pioneer Eugene W. Hilgard, journalist and financier Henry Villard, and abolitionist William Lloyd Garrison.

[1] By isolating and defining nucleic acid and the nucleobases, he provided the necessary precursors that led to the double-helix model of DNA, diffraction photographed by Rosalind Franklin, further devised by James D. Watson and Francis Crick in 1953.

[2] " … his elucidation of the chemical nature of some building blocks that make up nucleic acids and chromatine has secured immortality for this exeedingly modest and almost shy man.