Fireflies inhale oxygen and exhale light with help from an enzyme.

Image: Chinook / 
Image: Michael Krot / 
Image: Student of Marjan Eggermont at University of Calgary Schulich School of Engineering / 


“In a firefly bioluminescence reaction, an enzyme known as a luciferase uses adenosine triphosphate (ATP) to activate a molecule called a luciferin. The product of this reaction combines with molecular oxygen to produce an excited-state oxyluciferin species. When oxyluciferin relaxes back to its ground state, energy is released in the form of light…Jellyfish-like animals called ctenophores—can do without [ATP to jump-start bioluminescence]. Instead, they use a luciferin of intrinsically higher energy and prepackage it with oxygen in an enzyme known as a photoprotein. Calcium activates the reaction by changing the shape of the photoprotein, which releases the invested energy in the form of light.” (Pepling 2006:36)

Last Updated September 14, 2016