Herman Moritz Kalckar (26 March 1908 – 17 May 1991) was a Danish biochemist who pioneered the study of cellular respiration. Kalckar made a number of significant contributions to the development of 20th century biochemistry including: * a founder of bioenergetics; * enzymology, including novel assay techniques; * galactose metabolism in both microorganisms and animal tissues; * suggestion that strontium-90 levels in children’s deciduous teeth correlated with nuclear testing.