Thermogenin is found is:

Ans. b (Adipose tissue ). (Ref. Guyton ll,h/pg. 887; Harper's Biochemistry 26th ed. 217)BROWN ADIPOSE TISSUE# It is characterized by:- a well-developed blood supply- high content of mitochondria and cytochromes- but low activity of ATP synthase.# Norepinephrine liberated from sympathetic nerve endings is important in increasing lipolysis in the tissues.# Oxidation and phosphorylation are not coupled in mitochondria of this tissue and substrate level phosphorylation does not occur and thus oxidation produces much heat, and only little free energy is trapped in the form of ATP.# It is involved in metabolism particularly when heat generation is necessary.# In humans, it is present in normal individuals and responsible for "diet induced thermogenesis". However it is reduced or absent in obese individuals.# Thermogenin is an uncoupling protein that helps generate heat in a cell by allowing protons (H+) to go back into the mitochondrion without having to go through ATP synthase.- is found in brown adipose tissue, which is rich in mitochondria.- Hibernating animals use thermogenin to maintain their temperature while keeping their metabolic rate at a minimum.# A neonate has a considerable number of brown fat cells, and maximal sympathetic stimulation can increase the child's metabolism more than 100 per cent.# HIBERNOMA is a soft tissue tumor of brown fat.