The malate-aspartate shuttle and the glycerol-3-phosphate shuttle both transfer reducing equivalents from cytoplasmic NADH into mitochondria, but they differ in ATP yield. Which statement is correct?
- A The malate-aspartate shuttle yields 2.5 ATP, while the glycerol-3-phosphate shuttle yields 1.5 ATP ✓
- B Both shuttles yield 2.5 ATP per NADH
- C The glycerol-3-phosphate shuttle yields 2.5 ATP, while the malate-aspartate shuttle yields 1.5 ATP
- D Both shuttles yield 1.5 ATP per NADH
Correct answer: A. The malate-aspartate shuttle yields 2.5 ATP, while the glycerol-3-phosphate shuttle yields 1.5 ATP
Explanation
The malate-aspartate shuttle transfers electrons to mitochondrial NADH, yielding 2.5 ATP per NADH. The glycerol-3-phosphate shuttle transfers electrons to FADH2 via mitochondrial glycerol-3-phosphate dehydrogenase, yielding 1.5 ATP per NADH. This difference is physiologically significant in tissues like skeletal muscle that rely heavily on the glycerol-3-phosphate shuttle.
Reference: Lehninger Principles of Biochemistry, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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