In heart, liver and kidneys, cytoplasmic NADH employs malate-aspartate shuttle that yields
(a) 3 ATP
(b) 2 ATP
(c) 1 ATP
(d) No ATP

Options

A. 3 ATP
B. 2 ATP
C. 1 ATP
D. No ATP

Answer

To solve the question regarding the yield of ATP from the malate-aspartate shuttle in heart, liver, and kidneys, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Malate-Aspartate Shuttle**:
- The malate-aspartate shuttle is a mechanism that transports electrons from the cytoplasm into the mitochondria. It is particularly important in tissues like the heart, liver, and kidneys where high energy demand exists.

2. **Function of the Shuttle**:
- This shuttle allows for the transfer of reducing equivalents (in the form of NADH) from the cytosol to the mitochondrial matrix. In the cytoplasm, NADH cannot directly cross the mitochondrial membrane, so it is converted to malate.

3. **Conversion Process**:
- In the malate-aspartate shuttle, malate is formed from oxaloacetate and NADH. Once inside the mitochondria, malate is converted back to oxaloacetate, which regenerates NADH in the mitochondrial matrix.

4. **ATP Yield Calculation**:
- Each NADH molecule that enters the electron transport chain (ETC) can yield approximately 2.5 to 3 ATP molecules, depending on the shuttle system used. The malate-aspartate shuttle is known to yield 3 ATP per NADH because it efficiently transfers electrons into the mitochondrial ETC.

5. **Conclusion**:
- Therefore, the malate-aspartate shuttle in heart, liver, and kidneys yields **3 ATP** molecules from each NADH that is shuttled into the mitochondria.

### Final Answer:
(a) 3 ATP

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