21. Which statement is NOT correct regarding brown fat?
(1) It is present in negligible amount in new born baby
(2) It produces little ATP
(3) It produces more heat
(4) In Mitochondria associated with this electron transport chain and phosphorylation are uncoupled
Brown fat, or brown adipose tissue (BAT), plays a crucial role in thermogenesis, especially in newborns and hibernating mammals. It is specialized for heat production rather than ATP synthesis, thanks to the presence of uncoupling protein 1 (UCP1) in its mitochondria. Understanding its unique features helps clarify its physiological importance.
Evaluating the Statements About Brown Fat
(1) It is present in negligible amount in newborn baby
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This statement is incorrect.
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Brown fat is abundant in newborns, providing essential heat through nonshivering thermogenesis to maintain body temperature.
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Newborns rely heavily on BAT because their ability to shiver is limited.
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Adults have much less brown fat, mostly in specific regions like the neck and around large arteries.
(2) It produces little ATP
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This statement is correct.
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Brown fat mitochondria have uncoupled oxidative phosphorylation due to UCP1, which dissipates the proton gradient as heat rather than producing ATP.
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Hence, ATP synthesis is reduced compared to other tissues.
(3) It produces more heat
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This statement is correct.
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The primary function of brown fat is thermogenesis—generating heat by uncoupling electron transport from ATP synthesis.
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This heat production helps maintain body temperature in cold environments.
(4) In mitochondria associated with this, electron transport chain and phosphorylation are uncoupled
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This statement is correct.
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UCP1 in the inner mitochondrial membrane allows protons to re-enter the matrix without driving ATP synthase, uncoupling electron transport from phosphorylation.
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This uncoupling leads to rapid substrate oxidation and heat generation.
Summary Table
| Statement | Correctness | Explanation |
|---|---|---|
| (1) Present in negligible amount in newborn baby | Incorrect | Brown fat is abundant in newborns for thermogenesis. |
| (2) Produces little ATP | Correct | UCP1 uncouples ATP synthesis, reducing ATP production. |
| (3) Produces more heat | Correct | Brown fat generates heat via nonshivering thermogenesis. |
| (4) Electron transport and phosphorylation uncoupled | Correct | UCP1 uncouples oxidative phosphorylation, dissipating energy as heat. |
Conclusion
The statement that is NOT correct regarding brown fat is:
(1) It is present in negligible amount in newborn baby
8 Comments
Pallavi Ghangas
September 23, 2025present in negligible amount in newborn baby
Kirti Agarwal
September 24, 2025Statement A is incorrect
Roopal Sharma
September 25, 2025In new born babies brown fat is present in abundant number .
Heena Mahlawat
September 25, 2025Brown fat is abi abundantly present in new born babies
Manisha choudhary
September 27, 2025Brown fat newborn baby m aboundant hota h mitrochondria ki inner membrane m UCP-1 uncoupling protein hoti h jo without ATP synthesis H+ ions kaa matrix m back transport krwa deti h
Primary function thermogenesis hota h produce little ATP
Adult m km amount m hoti h kuch specific jagah jaise neck m large arteries k around hoti h
Manisha choudhary
September 27, 2025So statement – 1 is incorrect
Kajal
October 4, 2025New born have abundance of brown fat
Rishu
November 25, 2025In new born babies brown fat is present in abundant number