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  #1  
Old 04-13-2010
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Question Overnight Fast RBCs!

Which of the following is used as a metabolic energy source by erythrocytes after an overnight fast?

(A) Free fatty acids
(B) Glucose
(C) β-Hydroxybutyrate
(D) Pyruvate
(E) Triglycerides
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Old 04-13-2010
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Red Blood Cells depend exclusively on anaerobic glycolysis to produce energy (i.e. they have no mitochondria), irrespective of what the conditions are (glucose sufficiency after a meal or glucose depletion during fasting). Thus answer B is correct and answers A & E are not correct.

On the contrary, neurons may also use ketoacids as fuel, but this is not the case here (answers C & D are incorrect, although they seem very tempting).
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Old 04-13-2010
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Quote:
Originally Posted by ath.pantelis View Post
Red Blood Cells depend exclusively on anaerobic glycolysis to produce energy (i.e. they have no mitochondria), irrespective of what the conditions are (glucose sufficiency after a meal or glucose depletion during fasting). Thus answer B is correct and answers A & E are not correct.

On the contrary, neurons may also use ketoacids as fuel, but this is not the case here (answers C & D are incorrect, although they seem very tempting).
Simple concept but you nailed it in the head here for me. Thanks
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Old 04-13-2010
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tough question.I m stuck between glucose and pyruvate.Oh ok .B-glucose is correct.
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Old 04-14-2010
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Default yes B

Dr. ath's explanation was good enough. when come across this question no need to look at other choices. RBCs must and always use Glucose only. neurons (brain cells) can resort to ketones during depletion but the RBCs continue to use glucose.
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Old 04-14-2010
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i also thot abt glucose just now wen i saw!!!
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