Question

Which of the following is a biological uncoupler of oxidative phosphorylation?
A. Thermogenin.
B. 2, 4-Dichlorophenoxyacetic acid.
C. 2, 4-Dinitrophenol.
D. Ethylene diamine tetra-acetic acid.

Answer 1

A biological uncoupler is a protein found in mitochondria. It reduced ATP production and helps in heat generation.

Complete answer: The metabolic pathway in which cells use enzymes to oxidize nutrients is oxidative phosphorylation, thus releasing the chemical energy stored within to create adenosine triphosphate. This takes place within mitochondria in the majority of eukaryotes. Oxidative phosphorylation is carried out by almost all aerobic species.
As a transmembrane protein, thermogenin is also known as the uncoupling protein found in mitochondria. It is responsible for reducing the gradient of protons formed by oxidative phosphorylation. This is achieved by returning the protons to the matrix of the mitochondria by growing the inner mitochondrial membrane's permeability. Brown adipose tissue is rich in mitochondria, producing a protein that uncouples ADP oxidation, phosphorylation and decreases the production of ATP.
It consequently improves thermogenesis.

So, the correct answer is “Option A ”.

Additional Information: The heat generation mechanism in organisms is known as thermogenesis. This happens in all warm-blooded animal species. It is characterized as energy dissipation by heat generation and occurs in specialized tissues, including brown adipose tissue and skeletal muscle. Thermogenesis also occurs in some thermogenic plant species.

Note: A mitochondrial inner membrane protein and also a regulated proton channel or transporter, is the uncoupling protein (UCP). It is capable of dissipating the proton gradient produced by NADH-powered protons pumping from the mitochondrial matrix to the intermembrane mitochondrial space.