Firefly luciferase is the light-emitting enzyme responsible for the bioluminescence of fireflies and some types of beetles. This process occurs in specialized light-emitting organs, usually on a firefly's lower abdomen. The enzyme catalyses the firefly chemical luciferin, by binding to it and spending up the chemical reaction that combines oxygen molecules to produce oxyluciferin. Besides, oxygen this requires ATP. Because of the requirement of ATP, firefly luciferases have been used extensively in biotechnology. How do the enzymes speed up the chemical reactions and produce bioluminescent light?

Luciferase transforms luciferin into oxyluciferin while consuming ATP and O₂, and causes the emission of light.  

luciferin + ATP + luciferase + O₂ → oxyluciferin + AMP + CO₂+ luciferase + light

Explanation:

Fireflies are organisms that emit cold light by the process of bioluminescence. It is a chemical reaction of male individuals to attract the females that also respond by emitting light.

Luciferin is the molecule responsible for light emission. The chemical reaction involves the luciferin molecule, ATP molecule, enzyme luciferase, and oxygen molecule. Luciferin, the responsible molecule for light emission, is transformed into oxyluciferin by the enzyme luciferase. The enzyme consumes oxygen and ATP, which is the principal source of energy in living beings. Finally, a light of about 560 nm is released.

luciferin + ATP + luciferase + O₂ → oxyluciferin + AMP + CO₂+ luciferase + light

Almost the entire amount of energy involved in the reaction turns into luminous energy. ATP used for this light production process comes from the photosite´s mitochondrial electronic chain, responsible for the organism´s energy production.

Photosites are the cells responsible for light production, and many of their mitochondria are placed near the plasmatic membrane to catch oxygen.

Oxygen gets in the organisms through the lantern trachea. During the respiration process, photosites consume oxygen. Mitochondria placed in the cell periphery near the cell membrane catch the oxygen molecules and produce ATP. ATP produced by oxidative phosphorylation is involved in the production of oxyluciferin, turning into AMP.

Posteriorly, the oxyluciferin molecule is recycled back to luciferin. This process shows how chemical energy turns into luminous energy.

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.