During the first day of fasting, certain cells continue to depend entirely on blood glucose because they lack mitochondria and therefore cannot use fatty acids or ketones. These cells are:
- A Renal medullary cells
- B Skeletal muscle fibres
- C Erythrocytes ✓
- D Intestinal epithelial cells
Correct answer: C. Erythrocytes
Explanation
Mature erythrocytes have no mitochondria, so they generate ATP exclusively by anaerobic glycolysis and must consume glucose regardless of hormonal state; they also lack the ability to use any alternative fuel. Renal medulla and intestinal mucosa are glucose preferring but can oxidize ketones to some extent. Muscle switches readily to fatty acid oxidation during fasting. Erythrocyte glucose consumption feeds the Cori cycle, returning lactate to the liver for gluconeogenesis.
Reference: Lippincott's Illustrated Reviews: Biochemistry, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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