Question

The property of living organism to emit light by bioluminescence is exhibited by
A. Ctenoplana
B. Pennatula
C. Meandrina
D. Physalia

Answer 1

Hint: Bioluminescence is the property possessed by living organisms by virtue of which these organisms can emit light, and the living organisms possessing this property are called bioluminescence. The most popular example is fireflies.

Complete answer: The etymological meaning of the term ‘bioluminescence’ is the emission of light by living organisms. It is a type of chemiluminescence, where light is produced because of a chemical reaction. In bioluminescence, the chemical reaction takes place inside the body of the living organism, as the name suggests. In order to proceed with the chemical reaction, two important molecules are required namely, luciferin and luciferase or photoprotein. Among these chemicals, luciferin, being the light-emitting molecule is the one, which is mainly responsible for producing the light. The light that is emitted as a result of a chemical reaction is mainly due to the arrangement of luciferin molecules. Some organisms can synthesize luciferin on their own, such as Dinoflagellates, while some organisms that are unable to produce luciferin by their own, absorb it from other organisms by their symbiotic relationship. Squid comes under this category. It absorbs luciferin from bioluminescent bacteria. Ctenoplana is a small, marine animal, belonging to the genus of comb jellies. These organisms are transparent or sometimes colourless and belong to the phylum Ctenophora. These organisms exhibit the property of bioluminescence which is achieved by the activation of calcium-activated proteins. These proteins are called photoproteins. These photoproteins are present in special cells called photocytes, present in the organism.
Hence, the correct answer is option A.

Note: Land animals such as fireflies and beetles, mostly exhibit green or yellow, and sometimes red colour due to bioluminescence, while in case of ocean organisms, the colours mostly exhibited by them are blue-green or green.