q18 - kola

[ArchivalUser]

Which of the following occurs in nonshivering thermogenesis?

Options:

1. Glucose is oxidized to lactate

2. Fatty acids uncouple oxidative phosphorylation

3. Ethanol is formed

4. ATP is burned for heat production

5. Adipose tissue is functionally absent

[ArchivalUser]

444

[ArchivalUser]

The Correct Answer is: Fatty acids uncouple oxidative phosphorylation
Explanation:



Although metabolic poisons do uncouple oxidation of NADH from production of ATP, the uncoupling of oxidative phosphorylation does occur under certain normal biologic conditions. In brown fat (so called because of the large number of blood vessels), oxidation is uncoupled from phosphorylation so that heat is produced. This phenomenon is observed in newborn mammals, including humans, hibernating animals, and certain mammals that use it as an adaptation to the cold. In brown fat, fatty acids act as uncouplers of mitochondria. The catecholamine norepinephrine controls the release of the fatty acids, thereby regulating the process.